Package {wsMed}


Title: Within-Subject Mediation Analysis Using Structural Equation Modeling
Version: 1.2.0
Description: Within-subject mediation analysis using structural equation modeling. Examine how changes in an outcome variable between two conditions are mediated through one or more variables. Supports within-subject mediation analysis using the 'lavaan' package by Rosseel (2012) <doi:10.18637/jss.v048.i02>, and extends Monte Carlo confidence interval estimation to missing data scenarios using the 'semmcci' package by Pesigan and Cheung (2023) <doi:10.3758/s13428-023-02114-4>.
License: GPL (≥ 3)
Depends: R (≥ 4.1.0)
Encoding: UTF-8
RoxygenNote: 7.3.2
Suggests: rmarkdown, devtools, testthat, smcfcs (≥ 1.8.0)
Config/testthat/edition: 3
Imports: knitr, lavaan, semmcci, mice, semboottools, MASS, rlang, dplyr, ggplot2, methods, stats, graphics, utils
VignetteBuilder: knitr
LazyData: true
URL: https://yangzhen1999.github.io/wsMed/
BugReports: https://github.com/Yangzhen1999/wsMed/issues
NeedsCompilation: no
Maintainer: Wendie Yang <1581075494q@gmail.com>
Packaged: 2026-10-28 02:23:46 UTC; CodexSandboxOffline
Author: Wendie Yang ORCID iD [aut, cre], Shu Fai Cheung ORCID iD [aut]
Repository: CRAN
Date/Publication: 2026-10-28 08:20:02 UTC

Clean all CI column names into the standard form

Description

Clean all CI column names into the standard form

Usage

.clean_ci_names(df, ci_level = 0.95)

Fit SEM and run Monte-Carlo draws

Description

Fit SEM and run Monte-Carlo draws

Usage

.fit_and_mc(
  sem_model,
  data,
  Na = c("DE", "FIML"),
  R = 20000,
  alpha = 0.05,
  fixed.x = FALSE,
  verbose = TRUE,
  run_mc = TRUE,
  seed = NULL
)

Make CI column names

Description

Make CI column names

Usage

.make_ci_names(ci)

Create moderation output for wsMed

Description

Create moderation output for wsMed

Usage

.make_moderation(
  mc_res,
  data,
  W = NULL,
  MP = NULL,
  W_type = c("categorical", "continuous", "none"),
  alpha = 0.05,
  verbose = FALSE,
  point_estimates = NULL
)

Verbose message wrapper (internal)

Description

Verbose message wrapper (internal)

Usage

.v(..., verbose = TRUE)

Average relative increase in variance

Description

Average relative increase in variance

Usage

ARIVwrapper(between, within, M, k)

Arguments

between

Numeric matrix. Covariance between imputations \mathbf{V}_{\mathrm{between}}.

within

Numeric matrix. Covariance within imputations \mathbf{V}_{\mathrm{within}}.

M

Positive integer. Number of imputations.

k

Positive integer. Number of parameters.

Details

The average relative increase in variance is given by

\mathrm{ARIV} = \left( 1 + M^{-1} \right) \mathrm{tr} \left( \mathbf{V}_{\mathrm{between}} \mathbf{V}_{\mathrm{within}}^{-1} \right)

Value

Returns a numeric vector of length one.

Author(s)

Ivan Jacob Agaloos Pesigan


Generate a serial mediation model

Description

Dynamically generates a structural equation modeling (SEM) syntax for chained mediation analysis based on the prepared dataset. The function computes regression equations for mediators and the outcome variable, indirect effects along multi-step mediation paths, total effects, contrasts between indirect effects, and coefficients in different conditions.

Usage

GenerateModelCN(prepared_data, MP = character(0))

Arguments

prepared_data

A data frame returned by PrepareData(), containing the processed within-subject mediator and outcome variables. The data frame must include columns for difference scores (Mdiff) and average scores (Mavg) of mediators, as well as the outcome difference score (Ydiff).

MP

A character vector specifying which paths are moderated by variable(s) W. Valid entries include: - "a2", "a3", ...: moderation on the a paths (W → Mdiff), for mediators beyond M1. - "b2", "b3", ...: moderation on the b paths (Mdiff × W → Ydiff). - "b_1_2", "b_2_3", ...: moderation on cross-paths from one mediator to the next (e.g., M1 → M2). - "d2", "d3", ...: moderation on the d paths (Mavg × W → Ydiff). - "d_1_2", "d_2_3", ...: moderation on cross-paths from one Mavg to the next Mdiff. - "cp": moderation on the direct effect from X to Y (i.e., W → Ydiff).

      The function detects and inserts the correct interaction terms (e.g., \code{int_M2diff_W1}) based on these labels.

Details

This function is used to construct SEM models for chained mediation analysis. It automatically parses variable names from the prepared dataset and dynamically creates the necessary model syntax, including:

This model is suitable for chained mediation designs where mediators influence each other in a sequential manner, forming multi-step mediation paths.

Value

A character string representing the SEM model syntax for the specified chained mediation analysis.

Product moments

When a moderated path starts at an endogenous mediator, auxiliary product moment equations and covariances with its upstream disturbances preserve the joint predictor moment structure under reference recoding. These equations are not additional mediation paths. Genuine exogenous moments follow the fitting function's fixed.x setting; endogenous product moments are estimated.

See Also

PrepareData(), wsMed(), GenerateModelP()

Examples

# Example prepared data
prepared_data <- data.frame(
  M1diff = rnorm(100),
  M2diff = rnorm(100),
  M3diff = rnorm(100),
  M1avg = rnorm(100),
  M2avg = rnorm(100),
  M3avg = rnorm(100),
  Ydiff = rnorm(100)
)

# Generate SEM model syntax
sem_model <- GenerateModelCN(prepared_data)
cat(sem_model)


Generate a serial-parallel mediation model

Description

Dynamically generates a structural equation modeling (SEM) syntax for combined parallel and chained mediation analysis based on the prepared dataset. The function computes regression equations for mediators and the outcome variable, indirect effects for both parallel and chained mediation paths, total effects, contrasts between indirect effects, and coefficients in different X conditions.

Usage

GenerateModelCP(prepared_data, MP = character(0))

Arguments

prepared_data

A data frame returned by PrepareData(), containing the processed within-subject mediator and outcome variables. The data frame must include columns for difference scores (Mdiff) and average scores (Mavg) of mediators, as well as the outcome difference score (Ydiff).

MP

A character vector specifying which paths are moderated by variable(s) W. Acceptable values include: - "a2", "a3", ...: moderation on the a paths of parallel mediators (W → Mdiff). - "b2", "b3", ...: moderation on the b paths of parallel mediators (Mdiff × W → Ydiff). - "b_1_2", "b_1_3", ...: moderation on the paths from the chain mediator to parallel mediators. - "d_1_2", "d_1_3", ...: moderation on the paths from the chain mediator’s Mavg to parallel mediators. - "cp": moderation on the direct effect from X to Y (i.e., W → Ydiff).

      Each entry triggers inclusion of W’s main effect or interaction terms (e.g., \code{int_Mdiff_W}).

Details

This function is used to construct SEM models that combine parallel and chained mediation analysis. It automatically parses variable names from the prepared dataset and dynamically creates the necessary model syntax, including:

This model is suitable for designs where mediators include both a sequential chain (chained mediation) and independent parallel mediators.

Value

A character string representing the SEM model syntax for the specified combined parallel and chained mediation analysis.

Product moments

When a moderated path starts at an endogenous mediator, auxiliary product moment equations and covariances with its upstream disturbances preserve the joint predictor moment structure under reference recoding. These equations are not additional mediation paths. Genuine exogenous moments follow the fitting function's fixed.x setting; endogenous product moments are estimated.

See Also

PrepareData(), wsMed(), GenerateModelP(), GenerateModelCN()

Examples

# Example prepared data
prepared_data <- data.frame(
  M1diff = rnorm(100),
  M2diff = rnorm(100),
  M3diff = rnorm(100),
  M1avg = rnorm(100),
  M2avg = rnorm(100),
  M3avg = rnorm(100),
  Ydiff = rnorm(100)
)

# Generate SEM model syntax
sem_model <- GenerateModelCP(prepared_data)
cat(sem_model)


Generate a user-defined mediation model

Description

Generates lavaan model syntax for a user-defined within-subject mediation model. Users specify directed paths among mediators and from mediators to the outcome. The function automatically adds the corresponding difference and level components and identifies all indirect effects.

Usage

GenerateModelCustom(prepared_data, paths, MP = character(0))

Arguments

prepared_data

A data frame returned by PrepareData(). It must contain M1diff, M1avg, ..., and Ydiff.

paths

A character vector defining directed paths among mediators and from mediators to the outcome. For example: c("M1 -> M2", "M2 -> Y").

MP

A character vector identifying moderated paths. Supported labels follow the existing wsMed convention: a1, b1, d1, b_1_2, d_1_2, and cp.

Main effects of W are always labeled and used for conditional intercepts, including when a/cp is not explicitly listed in MP.

Value

A character string containing lavaan model syntax.

Product moments

When a moderated path starts at an endogenous mediator, auxiliary product moment equations and covariances with its upstream disturbances preserve the joint predictor moment structure under reference recoding. These equations are not additional mediation paths. Genuine exogenous moments follow the fitting function's fixed.x setting; endogenous product moments are estimated.

Examples

prepared_data <- data.frame(
  M1diff = rnorm(100),
  M1avg  = rnorm(100),
  M2diff = rnorm(100),
  M2avg  = rnorm(100),
  M3diff = rnorm(100),
  M3avg  = rnorm(100),
  Ydiff  = rnorm(100)
)

model <- GenerateModelCustom(
 prepared_data = prepared_data,
 paths = c(
   "M1 -> M3",
   "M1 -> Y",
   "M3 -> Y",
   "M2 -> Y"
 )
)

cat(model)


Generate a parallel mediation model

Description

Dynamically generates a structural equation modeling (SEM) syntax for parallel mediation analysis based on the prepared dataset. The function computes regression equations for mediators and the outcome variable, indirect effects, total effects, contrasts between indirect effect, and .

Usage

GenerateModelP(prepared_data, MP = character(0))

Arguments

prepared_data

A data frame returned by PrepareData(), containing the processed within-subject mediator and outcome variables. The data frame must include columns for difference scores (Mdiff) and average scores (Mavg) of mediators, as well as the outcome difference score (Ydiff).

MP

A character vector specifying which paths are moderated by variable(s) W. Valid values include: - "a1", "a2", ...: moderation on the a paths (W → Mdiff). - "b1", "b2", ...: moderation on the b paths (Mdiff × W → Ydiff). - "d1", "d2", ...: moderation on the d paths (Mavg × W → Ydiff). - "cp": moderation on the direct effect from X to Y (i.e., W → Ydiff).

      This argument controls which interaction terms (e.g., \code{int_Mdiff_W}, \code{int_Mavg_W}) are
      added to the corresponding regression equations.

Details

This function is used to construct SEM models for parallel mediation analysis. It automatically parses variable names from the prepared dataset and dynamically creates the necessary model syntax, including:

This model is suitable for parallel mediation designs where multiple mediators act independently.

Value

A character string representing the SEM model syntax for the specified parallel mediation analysis.

Product moments

When a moderated path starts at an endogenous mediator, auxiliary product moment equations and covariances with its upstream disturbances preserve the joint predictor moment structure under reference recoding. These equations are not additional mediation paths. Genuine exogenous moments follow the fitting function's fixed.x setting; endogenous product moments are estimated.

See Also

PrepareData(), wsMed(), GenerateModelCN()

Examples

# Example prepared data
prepared_data <- data.frame(
  M1diff = rnorm(100),
  M2diff = rnorm(100),
  M1avg = rnorm(100),
  M2avg = rnorm(100),
  Ydiff = rnorm(100)
)

# Generate SEM model syntax
sem_model <- GenerateModelP(prepared_data)
cat(sem_model)

Generate a parallel-serial mediation model

Description

Dynamically generates a structural equation modeling (SEM) syntax for mediation analysis that integrates both parallel and chained mediators. Unlike the Combined Parallel and Chained mediation model (GenerateModelCP), this function assumes that the chained mediator receives inputs from the parallel mediators and directly influences the outcome variable, emphasizing a downstream role for the chained mediator.

Usage

GenerateModelPC(prepared_data, MP = character(0))

Arguments

prepared_data

A data frame returned by PrepareData(), containing the processed within-subject mediator and outcome variables. The data frame must include columns for difference scores (Mdiff) and average scores (Mavg) of mediators, as well as the outcome difference score (Ydiff).

MP

A character vector specifying which paths are moderated by variable(s) W. Acceptable values include: - "a2", "a3", ...: moderation on the a paths (W → Mdiff). - "b2", "b3", ...: moderation on the b paths (Mdiff × W → Ydiff). - "b_2_1", "b_3_1", ...: moderation on the cross-paths from parallel mediators to the chain mediator (e.g., M2 → M1). - "d_2_1", "d_3_1", ...: moderation on the paths from parallel mediators’ centered means to M1. - "cp": moderation on the direct effect of X on Y (i.e., W → Ydiff).

      This argument controls which interaction terms (e.g., \code{int_Mdiff_W}, \code{int_Mavg_W}) are included
      in the regression equations. Variable names are automatically matched using the naming convention
      \code{"int_<predictor>_W<index>"}.

Details

This function is designed to build SEM models that integrate parallel and chained mediation structures. It automatically identifies variable names from the prepared dataset and generates the necessary model syntax, including:

This model is suitable for designs where mediators include both independent parallel paths and sequential chained paths, providing a comprehensive mediation analysis framework.

Value

A character string representing the SEM model syntax for the specified parallel and chained mediation analysis.

Product moments

When a moderated path starts at an endogenous mediator, auxiliary product moment equations and covariances with its upstream disturbances preserve the joint predictor moment structure under reference recoding. These equations are not additional mediation paths. Genuine exogenous moments follow the fitting function's fixed.x setting; endogenous product moments are estimated.

See Also

PrepareData(), wsMed(), GenerateModelP(), GenerateModelCN()

Examples

# Example prepared data
prepared_data <- data.frame(
  M1diff = rnorm(100),
  M2diff = rnorm(100),
  M3diff = rnorm(100),
  M1avg = rnorm(100),
  M2avg = rnorm(100),
  M3avg = rnorm(100),
  Ydiff = rnorm(100)
)

# Generate SEM model syntax
sem_model <- GenerateModelPC(prepared_data)
cat(sem_model)


Impute missing data using multiple imputation

Description

The ImputeData function performs multiple imputation on a data frame with missing values using the mice package. It handles missing data by creating multiple imputed datasets based on a specified imputation method and returns a list of completed data frames.

Usage

ImputeData(
  data_missing,
  m = 5,
  method = "pmm",
  seed = 123,
  predictorMatrix = NULL
)

Arguments

data_missing

A data frame containing missing values to be imputed. The function replaces values coded as -999 with NA before imputation.

m

An integer specifying the number of imputed datasets to generate.

method

A character string specifying the imputation method. Default is "pmm" (predictive mean matching).

seed

An integer for setting the random seed to ensure reproducibility. Default is 123.

predictorMatrix

An optional matrix specifying the predictor structure for the imputation model. Default is NULL, meaning that the function will use the default predictor matrix created by mice.

Details

This function replaces specified missing value placeholders (e.g., -999) with NA, and then applies the multiple imputation by chained equations (MICE) procedure to generate multiple imputed datasets. It supports flexible imputation methods and allows for specifying a custom predictor matrix.

Value

A list of m imputed data frames.

Author(s)

Wendie Yang, Shufai Cheung

Examples

# Example data with missing values
data <- data.frame(
  M1 = c(rnorm(99), rep(NA, 1)),
  M2 = c(rnorm(99), rep(NA, 1)),
  Y1 = rnorm(100),
  Y2 = rnorm(100)
)
# Perform multiple imputation
imputed_data_list <- ImputeData(data, m = 5)
# Display the first imputed dataset
head(imputed_data_list[[1]])


Convert lavaan model to RAM matrices

Description

Converts a lavaan-style matrix list into RAM (Reticular Action Model) format, including the A (asymmetric paths), S (symmetric paths), F (filter matrix), and M (means/intercepts) matrices.

Usage

Lav2RAM2(lav_mod)

Arguments

lav_mod

A named list of lavaan matrices including lambda, beta, theta, psi, and alpha.

Details

This function reorganizes the lavaan-style matrices into the RAM representation, commonly used for model standardization and transformation.

Value

A list with components:

A

Asymmetric path matrix (including factor loadings and structural paths)

S

Symmetric path matrix (variances and covariances)

F

Filter matrix mapping latent and observed variables

M

Row vector of intercepts/means


Process Monte Carlo samples for defined parameters in SEM

Description

A wrapper for the internal .MCDef() function from the semmcci package. This function processes Monte Carlo samples to compute defined parameters for structural equation modeling (SEM).

Usage

MCDefWrapper(object, thetahat, thetahatstar_orig)

Arguments

object

A fitted lavaan SEM model object.

thetahat

A numeric vector of parameter estimates.

thetahatstar_orig

A matrix of Monte Carlo samples, where rows represent samples and columns represent parameters.

Details

This function takes Monte Carlo samples of parameter estimates and a fitted SEM model object to compute the defined parameters (e.g., indirect effects or user-defined contrasts) based on the model syntax. It is particularly useful for examining derived quantities in SEM analyses using Monte Carlo methods.

Value

A matrix of computed defined parameters for each Monte Carlo sample.

See Also

MCMI2(), RunMCMIAnalysis()


Monte Carlo confidence intervals for multiple imputation SEM models

Description

Computes Monte Carlo confidence intervals (MCCI) for structural equation models (SEM) fitted to multiple imputed datasets. This function integrates SEM fitting across imputed datasets, pools the results, and generates confidence intervals through Monte Carlo sampling.

Usage

MCMI2(
  sem_model,
  imputations,
  R = 20000L,
  alpha = c(0.001, 0.01, 0.05),
  decomposition = "eigen",
  pd = TRUE,
  tol = 1e-06,
  seed = NULL,
  estimator = "ML",
  se = "standard",
  missing = "listwise",
  fixed.x = FALSE
)

Arguments

sem_model

A character string specifying the SEM model syntax.

imputations

A list of data frames, where each data frame represents an imputed dataset.

R

An integer specifying the number of Monte Carlo samples. Default is 20000L.

alpha

A numeric vector specifying significance levels for the confidence intervals. Default is c(0.001, 0.01, 0.05).

decomposition

A character string specifying the decomposition method for the covariance matrix. Default is "eigen". Options include "chol", "eigen", or "svd".

pd

A logical value indicating whether to ensure positive definiteness of the covariance matrix. Default is TRUE.

tol

A numeric value specifying the tolerance for positive definiteness checks. Default is 1e-06.

seed

An optional integer specifying the random seed for reproducibility. Default is NULL.

estimator

A character string specifying the estimator for SEM fitting. Default is "ML" (Maximum Likelihood).

se

A character string specifying the type of standard errors to compute. Default is "standard".

missing

A character string specifying the method for handling missing data in SEM fitting. Default is "listwise".

fixed.x

Whether exogenous covariates are treated as fixed in every imputation. Defaults to FALSE, consistently with wsMed().

Details

This function is designed for SEM models that require multiple imputation to handle missing data. It performs the following steps:

This function supports custom estimators, handling of missing data, and precision adjustments for Monte Carlo sampling. It is particularly useful for mediation analysis or complex SEM models where missing data are addressed using multiple imputation.

With decomposition = "eigen", Monte Carlo sampling uses the principal symmetric covariance square root. Equivalent eigenvector signs and repeated-eigenvalue bases therefore produce the same draws up to numerical precision. Fixed-seed draws differ from wsMed 1.1.0; the target distribution and pooled point estimates are unchanged. Reproducing the complete analysis also requires matching data, imputation settings, and software dependencies.

Value

An object of class semmcci containing:

See Also

lavaan::sem(), semmcci::MC(), semmcci::MCStd()

Examples

# Example SEM model
sem_model <- "
  Ydiff ~ b1 * M1diff + cp * 1
  M1diff ~ a1 * 1
  indirect := a1 * b1
  total := cp + indirect
"

# Example imputed datasets
imputations <- list(
  data.frame(M1diff = rnorm(100), Ydiff = rnorm(100)),
  data.frame(M1diff = rnorm(100), Ydiff = rnorm(100))
)

# Compute Monte Carlo confidence intervals
result <- MCMI2(
  sem_model = sem_model,
  imputations = imputations,
  R = 1000,
  alpha = c(0.05, 0.01),
  seed = 123
)

Monte Carlo summary for standardized estimates

Description

Computes standardized estimates, standard errors, and confidence intervals based on Monte Carlo samples from a semmcci object. This function fully standardizes both point estimates and sampling distributions (including intercepts).

Usage

MCStd2(mc, alpha = c(0.001, 0.01, 0.05))

Arguments

mc

A Monte Carlo result object of class semmcci, typically from MC() or MCMI().

alpha

A numeric vector of significance levels (default: c(0.001, 0.01, 0.05)).

Details

The function standardizes the sampling distribution using StdLav2() on each Monte Carlo draw, then summarizes the distribution into SEs and quantile-based confidence intervals. Invalid draws are excluded jointly and reported in the standardization_diagnostics attribute (requested, valid, invalid, indices and reasons).

Value

A data frame containing:

Parameter

Parameter name

Estimate

Standardized point estimate

SE

Standard deviation of standardized samples

R

Number of valid joint Monte Carlo replications

CI columns

Multiple confidence intervals based on alpha


Wrapper for internal multiple imputation combining function

Description

A wrapper function for the internal .MICombine() function from the semmcci package. This function pools parameter estimates and covariance matrices from multiple imputed datasets using Rubin's rules.

Usage

MICombineWrapper(coefs, vcovs, M, k, adj = FALSE)

Arguments

coefs

A list of numeric vectors, where each vector contains the parameter estimates from one imputed dataset.

vcovs

A list of numeric matrices, where each matrix represents the covariance matrix of the parameter estimates for one imputed dataset.

M

An integer indicating the number of imputations.

k

An integer specifying the number of parameters in the SEM model.

adj

A logical value indicating whether to apply an adjustment for finite samples. Default is TRUE.

Details

This wrapper provides an abstraction over the internal .MICombine() function from the semmcci package, allowing it to be used within your package without directly exposing the internal function. It is primarily designed for use within workflows that involve multiple imputation and structural equation modeling (SEM). Rubin's rules are applied to compute pooled parameter estimates and their covariance matrices.

Value

A list containing the pooled estimates and covariance matrix:

See Also

RunMCMIAnalysis()


Prepare data for two-condition mediation

Description

PrepareData() transforms raw pre/post data into the set of variables required by the wsMed workflow. It handles mediators, outcome, within-subject controls, between-subject controls, moderators, and all necessary interaction terms, while automatically centering / dummy-coding variables as needed.

Usage

PrepareData(
  data,
  M_C1,
  M_C2,
  Y_C1,
  Y_C2,
  C_C1 = NULL,
  C_C2 = NULL,
  C = NULL,
  C_type = NULL,
  W = NULL,
  W_type = NULL,
  center_W = TRUE,
  keep_W_raw = TRUE,
  keep_C_raw = TRUE
)

Arguments

data

A data frame with the raw pre/post measures.

M_C1, M_C2

Character vectors: mediator names at occasion 1 and 2 (equal length).

Y_C1, Y_C2

Character scalars: outcome names at occasion 1 and 2.

C_C1, C_C2

Optional character vectors: within-subject control names.

C

Optional character vector: between-subject control names.

C_type

Optional vector of the same length as C. Each element is one of "continuous", "categorical", or "auto" (default). Ignored when C = NULL.

W

Optional character scalar: one moderator column name.

W_type

Optional vector of the same length as W. Same coding as C_type. Ignored when W = NULL.

center_W

Logical. Whether to center the moderator variable W.

keep_W_raw, keep_C_raw

Logical. If TRUE, keep the original W / C columns in the returned data.

Details

The function performs the following steps:

  1. Outcome difference: Ydiff = Y_C2 - Y_C1.

  2. Mediator variables for each pair (M_C1[i], M_C2[i]):

    • Mi_diff = M_C2 - M_C1

    • Mi_avg is the mean-centered average of the two occasions.

  3. Between-subject controls C:

    • Continuous variables are grand-mean centered (Cb1, Cb2, ...).

    • Categorical variables (binary or multi-level) are expanded into k - 1 dummy variables (Cb1_1, Cb2_1, Cb2_2, ...), using the first level as the reference.

  4. Within-subject controls Cw: difference and centered-average versions (Cw1diff, Cw1avg, ...).

  5. Moderator W (at most one):

    • Continuous variables are grand-mean centered (W1, W2, ...).

    • Categorical variables are dummy-coded in the same way as C.

  6. Interaction terms between each moderator column and each mediator column:

    • int_<Mi_diff>_<Wj>, int_<Mi_avg>_<Wj>.

  7. Two attributes are added to the returned data:

    • "W_info": raw names, dummy names, level mapping

    • "C_info": same structure for between-subject controls.

Row counts are preserved even if input factors contain NA values (model.matrix is called with na.action = na.pass).

Value

A data frame containing at minimum:

plus the attributes "W_info" and "C_info" described above.

See Also

PrepareMissingData, GenerateModelP, wsMed, wsmed_categorical

Examples

set.seed(1)
raw <- data.frame(
  A1 = rnorm(50), A2 = rnorm(50),   # mediator 1
  B1 = rnorm(50), B2 = rnorm(50),   # mediator 2
  C1 = rnorm(50), C2 = rnorm(50),   # outcome
  D1 = rnorm(50), D2 = rnorm(50),   # within-subject control
  W_bin  = sample(0:1, 50, TRUE),   # between-subject binary C
  W_fac3 = factor(sample(c("Low","Med","High"), 50, TRUE)) # moderator W
)

prep <- PrepareData(
  data  = raw,
  M_C1  = c("A1","B1"), M_C2 = c("A2","B2"),
  Y_C1  = "C1",         Y_C2 = "C2",
  C_C1  = "D1",         C_C2 = "D2",
  C     = "W_bin",      C_type = "categorical",
  W     = "W_fac3",     W_type = "categorical"
)
head(prep)


Prepare data with missing values for mediation analysis

Description

Handles missing values in the dataset through multiple imputation and prepares the imputed datasets for within-subject mediation analysis. The function imputes missing data, processes each imputed dataset, and provides diagnostics for the imputation process.

Usage

PrepareMissingData(
  data_missing,
  m = 5,
  method_num = "pmm",
  seed = 123,
  M_C1,
  M_C2,
  Y_C1,
  Y_C2,
  C_C1 = NULL,
  C_C2 = NULL,
  C = NULL,
  C_type = NULL,
  W = NULL,
  W_type = NULL,
  center_W = TRUE,
  keep_W_raw = TRUE,
  keep_C_raw = TRUE
)

Arguments

data_missing

A data frame containing the raw dataset with missing values.

m

An integer specifying the number of imputations to perform. Default is 5.

method_num

Character; imputation method for numeric variables (for example, "pmm", "norm"). Default is "pmm".

seed

An integer specifying the random seed for reproducibility. Default is 123.

M_C1

A character vector of column names representing mediators at condition 1.

M_C2

A character vector of column names representing mediators at condition 2. Must match the length of M_C1.

Y_C1

A character string representing the column name of the outcome variable at condition 1.

Y_C2

A character string representing the column name of the outcome variable at condition 2.

C_C1

Character vector of within-subject control variable names (condition 1).

C_C2

Character vector of within-subject control variable names (condition 2).

C

Character vector of between-subject control variable names.

C_type

Optional vector of the same length as C. Each element is "continuous", "categorical", or "auto" (default). Ignored when C = NULL.

W

A character vector specifying the names of moderator variables that are used to generate interaction terms with mediators. These variables will be included in the imputation model and passed to PrepareData. Default is NULL.

W_type

Optional vector of the same length as W. Same coding as C_type. Ignored when W = NULL.

center_W

Logical. Whether to center the moderator variable W.

keep_W_raw, keep_C_raw

Logical; keep the original W / C columns in the returned data?

Details

This function is designed to preprocess datasets with missing values for mediation analysis. It performs the following steps:

This function integrates imputation and data preparation, ensuring that the resulting datasets are ready for subsequent mediation analysis.

Value

A list containing:

processed_data_list

A list of m data frames, each representing an imputed and processed dataset ready for within-subject mediation analysis.

imputation_summary

A summary of the imputation process, including diagnostics and convergence information.

See Also

PrepareData, ImputeData, wsMed

Examples

# Example dataset with missing values
data("example_data", package = "wsMed")
set.seed(123)
example_dataN <- mice::ampute(
  data = example_data,
  prop = 0.1
)$amp

# Prepare the dataset with multiple imputations
prepared_missing_data <- PrepareMissingData(
  data_missing = example_dataN,
  m = 5,
  M_C1 = c("A2", "B2"),
  M_C2 = c("A1", "B1"),
  Y_C1 = "C2",
  Y_C2 = "C1"
)

# Access processed datasets
processed_data_list <- prepared_missing_data$processed_data_list
imputation_summary  <- prepared_missing_data$imputation_summary


Convert standardized RAM back to lavaan matrices

Description

Converts a standardized RAM object back to lavaan-style matrix structure. Preserves residual covariances on their transformed scales.

Usage

RAM2Lav2(ram, lav_mod, standardized = FALSE)

Arguments

ram

A RAM list containing standardized matrices (A, S, F, and M).

lav_mod

A lavaan-style matrix list (e.g., GLIST) to be updated.

standardized

Retained for compatibility; RAM covariances are already rescaled.

Details

This function restores the internal lavaan model matrix structure from a RAM representation.

Value

A modified lavaan-style matrix list with updated lambda, beta, theta, psi, and alpha.


Generate Gaussian random variates using singular value decomposition

Description

Generate Gaussian random variates using singular value decomposition

Usage

RandomGaussianSVDwrapper(Z, svd)

Arguments

Z

Numeric matrix. n by k matrix of independent random variates from the standard univariate normal distribution \mathbf{Z}.

svd

Object. Result of svd().

Value

Numeric matrix.

Author(s)

Ivan Jacob Agaloos Pesigan


Monte Carlo SEM with multiple imputation (wsMed workflow)

Description

RunMCMIAnalysis() is a helper that:

  1. imputes missing data via PrepareMissingData;

  2. generates all WsMed variables in each completed data set;

  3. fits the user-supplied SEM model to each replicate; and

  4. pools the results via MCMI2(), producing Monte Carlo confidence intervals (MCCI) for all model parameters.

Usage

RunMCMIAnalysis(
  data_missing,
  m = 5,
  method_num = "pmm",
  seed = 123,
  M_C1,
  M_C2,
  Y_C1,
  Y_C2,
  C_C1 = NULL,
  C_C2 = NULL,
  C = NULL,
  C_type = NULL,
  W = NULL,
  W_type = NULL,
  keep_W_raw = TRUE,
  keep_C_raw = TRUE,
  sem_model,
  Na = "MI",
  R = 20000L,
  alpha = c(0.001, 0.01, 0.05),
  decomposition = "eigen",
  pd = TRUE,
  tol = 1e-06,
  fixed.x = FALSE
)

Arguments

data_missing

Data frame with missing values.

m

Integer, number of imputations. Default 5.

method_num

Character, imputation method for numeric variables (e.g., "pmm", "norm"). Default "pmm".

seed

Integer random seed (passed to mice and MCMI2).

M_C1, M_C2

Character vectors: mediator names at condition 1 & 2 (same length).

Y_C1, Y_C2

Character scalars: outcome names at condition 1 & 2.

C_C1, C_C2

Optional character vectors: within-subject controls.

C

Optional character vector: between-subject controls.

C_type

Optional vector (length = C); each element "continuous", "categorical", or "auto" (default).

W

Optional character vector: moderator name(s).

W_type

Optional vector (length = W); same coding as C_type.

keep_W_raw, keep_C_raw

Logical; keep raw W / C columns in the processed data? Defaults TRUE.

sem_model

Character string, lavaan syntax of the SEM to be fitted.

Na

Character, missing-data strategy. Currently only "MI" is implemented.

R

Integer, number of Monte Carlo samples (default 20000L).

alpha

Numeric vector, significance levels for two-sided CIs (default c(0.001, 0.01, 0.05)).

decomposition

Decomposition used by MCMI2() ("eigen" | "chol" | "svd"). Default "eigen".

pd

Logical, enforce positive-definite covariance (default TRUE).

tol

Numeric tolerance for PD checks. Default 1e-6.

fixed.x

Whether to treat exogenous covariates as fixed in every imputation.

Details

Internally the function calls:

Only the missing-data strategy Na = "MI" is supported.

Value

A list with three elements:

mc_result

A semmcci object returned by MCMI2().

first_imputed_data

The first processed data frame (useful for inspection or plotting).

imputation_summary

Diagnostics from PrepareMissingData().

See Also

PrepareMissingData, PrepareData, MCMI2, wsMed


Standardize parameter estimates in a lavaan model

Description

Applies full standardization (including intercepts) to a fitted lavaan model by converting to RAM form, performing standardization, and converting back to lavaan matrix structure.

Usage

StdLav2(
  est,
  object,
  marginal_variances = object@external$wsmed_mi_marginal$point
)

Arguments

est

A numeric vector of parameter estimates (free parameters).

object

A fitted lavaan model object (used to extract model structure).

marginal_variances

Optional jointly pooled MI marginal variances.

Details

The function extracts the model's RAM representation via Lav2RAM2, applies StdRAM2 standardization, restores the standardized GLIST via RAM2Lav2, and retrieves standardized user-defined parameter estimates with lav_model_get_parameters().

Value

A numeric vector of fully standardized parameter estimates (including intercepts and defined parameters).


Standardize RAM matrices

Description

Performs standardization of RAM matrices by rescaling path and variance structures using the implied covariance matrix. Intercepts are also standardized.

Usage

StdRAM2(ram_est, roles = NULL, marginal_variances = NULL)

Arguments

ram_est

A RAM object list with matrices A, S, F, and M as returned by Lav2RAM2().

roles

Internal list of dummy variable names and interaction components.

marginal_variances

Optional jointly pooled MI marginal variances.

Details

The function computes the implied covariance matrix \Sigma = (I - A)^{-1} S (I - A)^{-T}, extracts standard deviations, and performs standardization via D^{-1} scaling.

Value

A list of standardized RAM matrices:

A

Standardized asymmetric path matrix

S

Standardized symmetric path matrix

F

Unchanged filter matrix

M

Standardized intercept vector


Test for a positive definite matrix

Description

Returns TRUE if input is a positive definite matrix, and FALSE otherwise.

Usage

TestPositiveDefinitewrapper(eigen, tol = 1e-06)

Arguments

eigen

output of the eigen() function.

tol

Numeric. Tolerance.

Details

A k \times k symmetric matrix \mathbf{A} is positive definite if all of its eigenvalues are positive.

Value

Logical.

References

Wikipedia: Definite matrix


Monte Carlo sampling for parameter estimates

Description

Generates Monte Carlo samples for parameter estimates using a covariance matrix and a location vector. With eigen decomposition, sampling uses the principal symmetric square root of the covariance matrix.

Usage

ThetaHatStarWrapper(
  R = 20000L,
  scale,
  location,
  decomposition = "eigen",
  pd = TRUE,
  tol = 1e-06
)

Arguments

R

Integer. Number of Monte Carlo samples to generate.

scale

Numeric matrix. The covariance matrix of the parameter estimates.

location

Numeric vector. The mean (or location) of the parameter estimates.

decomposition

Character. Decomposition method for the covariance matrix. Options: "chol" (Cholesky), "eigen" (eigenvalue decomposition), "svd" (singular value decomposition). Default is "eigen".

pd

Logical. Ensure positive definiteness of the covariance matrix. Default is TRUE.

tol

Numeric. Tolerance for positive definiteness checks. Default is 1e-06.

Details

The eigen sampler is invariant to eigenvector signs and to rotations within eigenspaces with repeated eigenvalues, up to numerical precision. This changes fixed-seed draws relative to wsMed 1.1.0, while preserving their target distribution. It does not guarantee identical results across different fitted inputs, imputation algorithms, or software environments.

Value

A list containing:

See Also

MCMI2(), RunMCMIAnalysis()


Compute updated parameter estimates for SEM models

Description

A wrapper for the internal .ThetaHat() function from the semmcci package. This function computes updated parameter estimates for structural equation models (SEM) using pooled estimates from multiple imputations or Monte Carlo simulations.

Usage

ThetaHatWrapper(object, est = NULL)

Arguments

object

A fitted lavaan SEM model object.

est

A numeric vector of pooled parameter estimates, typically obtained from multiple imputations or Monte Carlo simulations.

Details

The function takes a fitted SEM model object and pooled parameter estimates to calculate the updated parameter values. It is particularly useful for combining results from multiple imputations or Monte Carlo samples to refine parameter estimates.

Value

A numeric vector of updated parameter estimates.

See Also

MCMI2(), RunMCMIAnalysis()

Examples

NULL


Adjusted total sampling covariance matrix

Description

Adjusted total sampling covariance matrix

Usage

TotalAdjwrapper(ariv, within)

Arguments

ariv

Numeric. Average relative increase in variance.

within

Numeric matrix. Covariance within imputations \mathbf{V}_{\mathrm{within}}.

Details

The adjusted total sampling covariance matrix is given by

\tilde{\mathbf{V}}_{\mathrm{total}} = \left( 1 + \mathrm{ARIV} \right) \mathbf{V}_{\mathrm{within}}

Author(s)

Ivan Jacob Agaloos Pesigan


Apply PrepareData to imputed datasets and return new mids object

Description

This function applies the PrepareData() preprocessing step to each imputed dataset in a mids object and returns a new mids object with the transformed data. It is designed for use in within-subject mediation analysis pipelines when working with multiply imputed data.

Usage

TransformMidsWithPrepareData(mids_obj, M_C1, M_C2, Y_C1, Y_C2)

Arguments

mids_obj

A mids object created by the mice package, containing multiply imputed datasets.

M_C1

A character vector specifying the names of mediator variables under Condition 1 (e.g., pre-test).

M_C2

A character vector specifying the names of mediator variables under Condition 2 (e.g., post-test).

Y_C1

A character string specifying the outcome variable under Condition 1.

Y_C2

A character string specifying the outcome variable under Condition 2.

Details

The function performs the following steps:

This enables subsequent analyses to operate on a version of the multiply imputed data where difference scores and averages have already been computed.

Value

A new mids object where each imputed dataset has been processed using PrepareData().


Append significance stars based on CI

Description

Append significance stars based on CI

Usage

add_sig(df)

Summarize effects with a continuous moderator

Description

analyze_mm_continuous() summarises Monte Carlo draws from a semmcci object when the moderator W is continuous. It reports moderated path coefficients, conditional indirect effects, conditional path coefficients, and effect curves across values of the moderator.

Usage

analyze_mm_continuous(
  mc_result,
  data,
  MP,
  W_raw_name = "W",
  ci_level = 0.95,
  W_values = NULL,
  n_curve = 120,
  digits = 8,
  point_estimates = NULL
)

Arguments

mc_result

A semmcci object returned by MCMI2().

data

A processed data frame containing the original moderator variable. This is typically the first component returned by PrepareData().

MP

Requested focal paths; all fitted W main effects enter conditional effects.

W_raw_name

A character string giving the name of the moderator variable in data. The default is "W".

ci_level

A numeric value between zero and one specifying the two-sided confidence level. The default is 0.95.

W_values

An optional numeric vector containing at least two distinct raw moderator values at which to evaluate the conditional effects. If NULL, the moderator mean and values one standard deviation below and above the mean are used.

n_curve

A positive integer specifying the number of moderator values used to construct each effect curve. The default is 120.

digits

A non-negative integer specifying the number of decimal places used to round the reported results. The default is 8.

point_estimates

Named plug-in parameter estimates. If omitted, the means of primitive coefficient draws are used.

Details

The function first summarises the coefficients associated with moderated paths, including interaction terms such as aw, bw, dw, and cpw, together with their corresponding base coefficients and confidence intervals.

It then evaluates conditional indirect effects and moderated path coefficients at three reference values of the moderator. By default, these values are the moderator mean and one standard deviation below and above the mean. Alternative reference values can be supplied through W_values.

Finally, the function evaluates the conditional indirect effects and moderated path coefficients over a moderator grid. These results can be used to plot effect curves or identify regions in which the confidence interval excludes zero.

An asterisk is added to an effect when its confidence interval excludes zero.

Value

A named list with the following components:

mod_coeff

A data frame summarising the moderated path coefficients, their corresponding base coefficients, and confidence intervals.

beta_coef

A data frame containing the conditional indirect effects at the three reference values of the moderator.

path_HML

A data frame containing the conditional moderated path coefficients at the three reference values of the moderator.

theta_curve

A data frame containing the conditional indirect effects evaluated over the moderator grid.

path_curve

A data frame containing the conditional path coefficients evaluated over the moderator grid.


Apply standardization to parameter definitions

Description

Replaces parameters in expressions with their standardized versions.

Usage

apply_standardization(definitions, std_map, path_std_map = list())

Arguments

definitions

A list of user-defined parameter expressions.

std_map

A named list mapping intercept parameter names to their observed variables.

path_std_map

A named list mapping slope parameters to predictor/outcome variables.

Value

A list of standardized parameter expressions.


Assert a scalar (whole-number) integer with optional bounds

Description

Assert a scalar (whole-number) integer with optional bounds

Usage

assert_scalar_int(
  x,
  name = deparse(substitute(x)),
  lower = NULL,
  upper = NULL,
  allow_null = FALSE
)

Bootstrap standard deviations for standardization

Description

Performs bootstrap sampling to estimate SDs of variables used in standardization.

Usage

bootstrap_sd_list(data, var_names, nboot = 20000, seed = NULL)

Arguments

data

A data frame.

var_names

A character vector of variable names.

nboot

Integer. Number of bootstrap samples.

seed

Integer. Random seed.

Value

A named list of numeric vectors (bootstrapped SD samples).


Build unstandardized parameter definitions

Description

Extracts parameter definition expressions from a fitted model.

Usage

build_definitions(fit)

Arguments

fit

A lavaan model object.

Value

A named list of parameter definitions.


Build path-specific standardization maps

Description

Constructs mapping of parameter labels to variables for standardization.

Usage

build_path_std_map(fit)

Arguments

fit

A fitted lavaan model.

Value

A named list: slopes (path_std_map).


Build standardization maps

Description

Constructs mapping of parameter labels to variables for standardization.

Usage

build_std_map(fit)

Arguments

fit

A fitted lavaan model.

Value

A named list: intercepts (std_map).


Basic contrasts for indirect effects and pre/post path coefficients

Description

calc_basic_contrasts() extracts two convenient sets of contrasts from a Monte-Carlo SEM result (semmcci object):

  1. All pairwise differences between indirect effects (⁠indirect_*⁠ columns);

  2. Pre-test (X_0) and post-test (X_1) coefficients for every primary b path, obtained with X_1 = (2b + d)/2, X_0 = X_1 - d.

Usage

calc_basic_contrasts(
  mc_result,
  ci_level = 0.95,
  digits = 3,
  point_estimates = NULL
)

Arguments

mc_result

A Monte-Carlo result of class "semmcci" (returned by MCMI2()).

ci_level

Confidence level for the CI (default 0.95).

digits

Decimal places to keep (default 3).

point_estimates

Named fitted parameter estimates, including defined effects.

Details

Each contrast is summarised with its plug-in estimate, sampling SD, and a symmetric 100(1-\alpha) % confidence interval. Helper functions mc_summary_pct() and fix_pct_names() ensure that the final CI columns are named, for example, ⁠2.5%CI.Lo⁠ and ⁠97.5%CI.Up⁠.

Value

A list with up to two data frames:

IE_contrasts

Pairwise contrasts of indirect effects, or NULL if fewer than two are present.

Xcoef

Rows ⁠X1_b*⁠ and ⁠X0_b*⁠ for every detected b path, or NULL if no b path is found.


Debug printer with indentation (internal)

Description

Debug printer with indentation (internal)

Usage

dbg(..., .lvl = 0, verbose = TRUE)

Evaluate unstandardized Monte Carlo definitions

Description

Evaluates user-defined parameter expressions from Monte Carlo samples without any standardization.

Usage

evaluate_definitions_unstd_v2(theta_star, definitions)

Arguments

theta_star

A matrix of Monte Carlo samples.

definitions

A named list of algebraic definitions (as strings).

Value

A data frame with R rows (simulations) and p + d columns (p = number of free parameters, d = number of defined parameters).


Evaluate standardized Monte Carlo expressions

Description

Evaluates user-defined parameters (defined via expressions) and standardized free parameters from Monte Carlo simulated samples. This version supports both intercept-based standardization and path-based standardization.

Usage

evaluate_definitions_v3(
  theta_star,
  definitions,
  std_map,
  sd_boot_list,
  sd_var_boot,
  path_std_map
)

Arguments

theta_star

A matrix of Monte Carlo samples.

definitions

A named list of parameter definitions (e.g., list(indirect := "a * b")).

std_map

A named character vector mapping intercept labels (e.g., a1) to variable names (e.g., M1diff).

sd_boot_list

A list of bootstrap SD samples for intercept variables.

sd_var_boot

A list of bootstrap SD samples for variables involved in slope paths.

path_std_map

A named list mapping path labels to a vector of (predictor, outcome) variable names.

Value

A data frame of R rows (simulations) * all parameters (standardized free + defined).


Simulated data for mediation tutorials

Description

Artificial data used to demonstrate model syntax, estimation, and categorical predictors. The labels do not identify substantive psychological constructs. This is distinct from the empirical manuscript dataset wsmed_examples().

Usage

example_data

Format

A tibble (data frame) with 100 rows and 14 variables:

A1, A2, A3

Numeric measurements for variable A at three conditions.

B1, B2, B3

Numeric measurements for variable B at three conditions.

C1, C2, C3

Numeric measurements for variable C at three conditions.

D1, D2, D3

Numeric measurements for variable D at three conditions.

Group

An unordered factor with levels high, med, and low, in that order.

W_Group

An unordered factor with levels high, med, and low, in that order.

Details

All columns are complete. A wsMed analysis selects two condition columns per outcome or mediator. The factor labels are nominal categories; they do not request an ordinal regression model. Set their level order explicitly before fitting to select a different reference category.

See Also

wsmed_examples(), wsmed_categorical

Examples

data(example_data)
dim(example_data)
levels(example_data$Group)

Extract all parameters and definitions

Description

Extracts free and defined parameters from a fitted lavaan model, and builds a dependency map of user-defined parameters.

Usage

extract_all_parameters(fit)

Arguments

fit

A lavaan model object.

Value

A list with:


Fix legacy CI column names in a data.frame

Description

Converts columns like CI[LL] / CI[UL] or CI.LL / CI.UL to the standard produced by .make_ci_names().

Usage

fix_ci_names(df, ci = 0.95)

Repair percent signs altered by make.names()

Description

Repair percent signs altered by make.names()

Usage

fix_pct_names(df)

Generate Monte Carlo samples

Description

Generates a Monte Carlo sample of model parameters from a multivariate normal distribution.

Usage

generate_mc_samples(fit, resolved_map, R = 20000, seed = NULL)

Arguments

fit

A fitted lavaan model.

resolved_map

A dependency map from resolve_all_dependencies().

R

Integer. Number of Monte Carlo samples to generate.

seed

Integer. Random seed.

Value

A numeric matrix of Monte Carlo samples.


Extract all variables needed for standardization

Description

Extracts predictor and outcome variable names from a path standardization map.

Usage

get_all_variables_from_path_map(path_std_map)

Arguments

path_std_map

A named list returned by build_path_std_map().

Value

A character vector of variable names.


Parse indirect paths from coefficient names

Description

Infers every unique mediation chain that can be constructed from a set of coefficient names following the WsMed naming convention (e.g., a1, b_1_3, d_2_1, b3). The function returns a list; each element describes one indirect effect:

Usage

get_indirect_paths(col_names)

Arguments

col_names

Character vector of coefficient names (typically colnames(mc_result$thetahatstar)).

Details

Internally the function:

  1. identifies all a, b, and d coefficients available in col_names;

  2. constructs a directed graph from X → Mi, Mi → Y, and Mi → Mj edges;

  3. runs a depth-first search from the exposure (X) to the outcome (Y);

  4. converts every node sequence (X → … → Y) into the corresponding coefficient sequence.

Duplicate paths (identical mediator ordering) are removed.

Value

A list of path descriptors; each element is itself a list with components path_name, coefs, and mediators. If no valid path exists, an empty list is returned.


Get safe number of CPUs for parallel processing

Description

Automatically returns 1 when on CI to avoid errors.

Usage

get_safe_ncpus()

Extract target variables for standardization

Description

Extracts variable names from a fitted SEM model and a definition map that are required for computing standardized estimates in Monte Carlo simulations. Specifically, it identifies intercept terms (e.g., ~1) involved in user-defined parameters such as indirect effects (e.g., indirect := a * b) that require standard deviations for standardization.

Usage

get_sd_target_variables(fit, definition_map, data)

Arguments

fit

A lavaan model object. Must be fitted with labels for defined parameters.

definition_map

A named list returned from resolve_all_dependencies(), mapping defined parameters (e.g., "indirect1") to their algebraic components (e.g., c("a1", "b1")).

data

A data frame used to fit the model, typically the original observed dataset. Used to validate the existence of variables.

Value

A character vector of variable names whose standard deviations are needed to standardize the intercept estimates in Monte Carlo confidence interval analysis.


Compare indirect effects across moderator levels

Description

Compare indirect effects across moderator levels

Usage

make_contrasts(df, value_col = "Estimate", contrast_col = "Contrast")

Compute Monte Carlo estimates, standard errors, and CIs (with percent labels)

Description

mc_summary_pct() summarizes a numeric vector of Monte Carlo samples x by computing its mean, standard deviation, and percentile-based confidence interval. The result is returned as a data.frame with column names that include percentage signs. This function is typically used to generate tables of mediation effects or path coefficient estimates with path labels.

Returned columns include:

Usage

mc_summary_pct(x, label, ci_level = 0.95, digits = 3)

Arguments

x

Numeric vector of Monte Carlo samples.

label

Character string for the value in the Path column of the output.

ci_level

Confidence level for the CI (default 0.95).

digits

Number of decimal places to retain (default 3).

Value

A data.frame containing the path label, estimate, standard error, and CI. Column names are formatted like "2.5%CI.Lo" and "97.5%CI.Up".


Null-coalescing operator

Description

Returns x unless it is NULL, otherwise returns y.

Usage

x %||% y

Plot conditional effects at moderator levels

Description

Draw point estimates and confidence intervals by categorical group or by the stored low, mean and high levels of a continuous moderator. Each effect is shown in its own panel. Categories are not joined by interpolating lines.

Usage

plot_conditional_effects(
  result,
  paths = NULL,
  type = c("indirect", "paths", "overall"),
  levels = NULL,
  standardized = FALSE,
  engine = c("mc", "boot"),
  labels = NULL,
  title = NULL,
  x_label = NULL,
  y_label = NULL,
  base_size = 12,
  ncol = NULL
)

Arguments

result

A result returned by wsMed().

paths

Optional character vector of effect identifiers, in display order. NULL selects all available effects. Both indirect_1 and indirect_effect_1 are accepted when they identify an available effect.

type

"indirect" for specific indirect effects, "paths" for available conditional path coefficients, or "overall" for total indirect and total effects.

levels

Optional group/level labels to select, in display order. NULL uses their stored order. For continuous W the labels are "-1 SD", "0 SD", "+1 SD"; the axis also displays stored raw W probe values.

standardized

Use standardized results, requested when fitting with standardized = TRUE. No scaling is recomputed from interval endpoints.

engine

For ci_method = "both", select "mc" or "boot". For a single engine its stored results are used.

labels

Optional named character vector mapping effect identifiers to display labels. Partial mappings are allowed.

title

Optional plot title.

x_label, y_label

Optional axis labels.

base_size

Base font size.

ncol

Optional number of facet columns.

Details

Intervals are the stored percentile conditional intervals, including jointly transformed scales for standardized results. They are individual intervals, not simultaneous confidence intervals.

Value

A ggplot object with plotted data and a wsmed_plot attribute.

See Also

plot_effects(), plot_contrasts()


Plot differences between mediation effects

Description

Draw contrast estimates and their confidence intervals relative to zero. With a moderator, contrasts compare groups or stored moderator levels within each effect. Without a moderator, specific indirect paths are compared with one another. The displayed subtraction order is explicit.

Usage

plot_contrasts(
  result,
  paths = NULL,
  type = c("indirect", "paths", "overall"),
  contrasts = NULL,
  standardized = FALSE,
  engine = c("mc", "boot"),
  labels = NULL,
  title = NULL,
  x_label = NULL,
  y_label = NULL,
  base_size = 12,
  ncol = NULL
)

Arguments

result

A result returned by wsMed().

paths

Optional character vector of effect identifiers, in display order. NULL selects all available effects. Both indirect_1 and indirect_effect_1 are accepted when they identify an available effect.

type

"indirect" for specific indirect effects, "paths" for available conditional path coefficients, or "overall" for total indirect and total effects.

contrasts

Optional exact contrast labels to select, in display order. NULL selects all. Inspect the corresponding result table or the returned plot's data$Contrast for available labels.

standardized

Use standardized results, requested when fitting with standardized = TRUE. No scaling is recomputed from interval endpoints.

engine

For ci_method = "both", select "mc" or "boot". For a single engine its stored results are used.

labels

Optional named character vector mapping effect identifiers to display labels. Partial mappings are allowed.

title

Optional plot title.

x_label, y_label

Optional axis labels.

base_size

Base font size.

ncol

Optional number of facet columns.

Details

Moderator contrasts use the existing joint-draw contrast tables. Without a moderator, only type = "indirect" is available: contrasts are computed from the stored joint draws, with point estimates evaluated at fitted/pooled parameters. Their intervals are percentile intervals. Standardized draws use the same draw-specific marginal endpoint scales as other standardized effects. No model is refitted. Interval endpoints for two separate effects are never subtracted to construct a contrast CI. paths and labels apply to effect panels when a moderator is present; without a moderator, paths selects the indirect effects to compare and labels maps the full contrast labels. Continuous overall contrasts are unavailable when the fitted result does not contain that contrast table.

Value

A ggplot object with plotted data and a wsmed_plot attribute.

See Also

plot_effects(), plot_conditional_effects()


Forest plot of mediation effects

Description

Plot fitted indirect effects, the total indirect effect, the direct effect (cp) and the total effect with their stored confidence intervals. With a moderator these are effects at the model's reference value (centered continuous W = 0, or the reference category), not averages across W. Use plot_conditional_effects() to show selected moderator levels instead.

Usage

plot_effects(
  result,
  paths = NULL,
  standardized = FALSE,
  engine = c("mc", "boot"),
  labels = NULL,
  title = NULL,
  x_label = NULL,
  y_label = NULL,
  base_size = 12
)

Arguments

result

A result returned by wsMed().

paths

Optional character vector of effect identifiers, in display order. NULL selects all available effects. Both indirect_1 and indirect_effect_1 are accepted when they identify an available effect.

standardized

Use standardized results, requested when fitting with standardized = TRUE. No scaling is recomputed from interval endpoints.

engine

For ci_method = "both", select "mc" or "boot". For a single engine its stored results are used.

labels

Optional named character vector mapping effect identifiers to display labels. Partial mappings are allowed.

title

Optional plot title.

x_label, y_label

Optional axis labels.

base_size

Base font size.

Details

MC intervals come from the parameter draws (or the stored standardized parameter table). Bootstrap plots use the bootstrap limits, not the normal-theory limits that may also be present in the table. New workflow objects use wsmed_plots. Both interfaces expose full-precision estimate, conf.low, and conf.high columns in the plotted data; legacy column names remain available. Interval conventions are not silently changed.

Value

A ggplot object. Its data contains the plotted estimates and CI.LL/CI.UL limits. The wsmed_plot attribute records the selected engine, scale and confidence level. Use ggplot2::ggsave() to export it.

See Also

plot_conditional_effects(), plot_contrasts(), plot_moderation_curve()


Plot conditional effects across a continuous moderator

Description

Plot a conditional indirect effect, total effect or path coefficient with its pointwise confidence band. Highlight stored grid values whose interval excludes zero. Boundary labels use raw moderator units, not sample percentiles.

Usage

plot_moderation_curve(
  result,
  path_name,
  title = NULL,
  x_label = "Moderator (W, raw units)",
  y_label = "Estimate",
  ns_fill = "#FEE0D2",
  sig_fill = "#C7E9C0",
  alpha_ci = 0.35,
  alpha_sig = 0.35,
  base_size = 14,
  standardized = FALSE,
  engine = c("mc", "boot")
)

Arguments

result

A result returned by wsMed() with a continuous moderator.

path_name

One stored effect identifier, such as "indirect_effect_1_2", "total_indirect" or "b_1_2". "indirect_1_2" is also accepted as an alias.

title

Optional plot title.

x_label, y_label

Axis labels. The default x axis uses raw W units.

ns_fill

Colour of the complete confidence band.

sig_fill

Colour of the regions whose pointwise CI excludes zero.

alpha_ci, alpha_sig

Opacity of the band and highlighted regions.

base_size

Base font size.

standardized

Use the stored standardized conditional results.

engine

For ci_method = "both", select "mc" or "boot".

Details

Highlighted intervals are approximate ranges on the stored grid, not exact Johnson–Neyman boundaries or simultaneous confidence regions. A label ⁠[a, b]⁠ reports the first and last qualifying grid values. An isolated qualifying point is marked by a vertical line. Missing confidence limits break a highlighted range. The displayed confidence level follows result$alpha; no fixed p-value threshold is implied.

Value

A ggplot object. Its data contains the selected curve; the wsmed_regions attribute contains raw-unit grid interval endpoints. The wsmed_plot attribute records engine, scale and confidence level.

See Also

plot_effects(), plot_conditional_effects(), plot_contrasts()


Print formatted SEM model syntax

Description

Formats and prints the SEM model syntax generated by GenerateModelCN, GenerateModelCP, GenerateModelP, and GenerateModelPC. It organizes the equations into labeled sections for better readability.

Usage

printGM(x, ...)

Arguments

x

A list or character string containing SEM model syntax. If x is a wsMed() result, it will extract and print the model syntax. If x is a ⁠GenerateModel*()⁠ result, it will format and print the model.

...

Additional arguments (not used).

Value

Invisibly returns the formatted SEM model syntax.

Examples

data(example_data)
head(example_data)
prepared_data <- PrepareData(
  data = example_data,
  M_C1 = c("A1", "B1"),
  M_C2 = c("A2", "B2"),
  Y_C1 = "C1",
  Y_C2 = "C2"
)
sem_model <- GenerateModelPC(prepared_data)
printGM(sem_model)

Resolve dependencies of defined parameters

Description

Recursively resolves all free parameters involved in each defined parameter.

Usage

resolve_all_dependencies(def_map)

Arguments

def_map

A definition map produced by extract_all_parameters().

Value

A list mapping each defined parameter to its dependent free parameters.


Run Monte Carlo-based mediation inference

Description

Performs Monte Carlo simulation to estimate confidence intervals for both unstandardized and (optionally) standardized mediation parameters, based on fitted SEM models.

Usage

run_mc_mediation(
  fit,
  data,
  standardized = FALSE,
  R = 20000,
  seed = 123,
  alpha = 0.05,
  alphastd = 0.05
)

Arguments

fit

A fitted lavaan model.

data

The dataset used for the fitted model.

standardized

Logical. If TRUE, standardized results will also be returned. Default is FALSE.

R

Integer. Number of Monte Carlo replications. Default is 20000.

seed

Integer. Random seed for reproducibility. Default is 123.

alpha

Numeric value for the confidence level of unstandardized Monte Carlo intervals. Default is 0.05.

alphastd

Numeric value for the confidence level of standardized Monte Carlo intervals. Default is 0.05.

Value

A list with unstandardized and (if requested) standardized results. Each result includes Monte Carlo estimates, SEs, and CIs.


Sort parameters for printing in SEM output

Description

Sorts a parameter table by conceptual priority for presentation purposes. This function is designed to support formatted output of mediation and SEM results by organizing parameters such as a-paths, b-paths, indirect effects, contrasts, etc.

Usage

sort_parameters(df)

Arguments

df

A data frame that contains a column named Parameter (e.g., from Monte Carlo CI output).

Details

This is an internal helper function used by print.WsMed() to ensure that printed tables of standardized or unstandardized estimates appear in a logical and human-readable order.

Value

A reordered version of the same data frame, with rows sorted according to a predefined logical structure:

  1. a-paths (e.g., a1, a2, ...)

  2. b-paths (e.g., b1, b2, ...)

  3. d-paths (e.g., d1, d2, ...)

  4. indirect effects (e.g., ind1, ind2, ...)

  5. direct effect

  6. total indirect

  7. total effect

  8. contrasts (e.g., ind1-ind2, ind2-ind3)

  9. X-condition path terms (e.g., X1_b1, X0_b1, ...)


Standardize conditional mediation results using existing joint draws

Description

Standardize conditional mediation results using existing joint draws

Usage

standardize_moderation(object)

Arguments

object

A wsMed result with a moderator and stored MC or bootstrap draws.

Details

Conditional indirect and total effects are divided by the marginal model-implied SD of Ydiff. Conditional paths use their endpoint scales. Moderator probe values remain fixed in raw units; continuous interaction coefficients in mod_coeff are reported per SD of W. Dummy variables retain 0/1 units. Coefficients and scales are transformed jointly for each draw. Intervals are percentile intervals, as in the raw conditional tables. Metadata attributes record scales, probe conventions and draw diagnostics. With fixed.x=TRUE, external moments are held fixed. MI uses pooled primitive parameters and the existing first-imputation probing reference. For models with endogenous products, marginal variances are pooled jointly with coefficients before taking square roots, retaining their sampling covariance. Saved endogenous-product fits and MI draws require compatible algorithm identifiers. Refit unversioned old models rather than restandardizing them.

Value

A moderation list with the same conditional tables and curves as the raw output, or a list with mc and boot components for ci_method="both".


Summarize Monte Carlo simulation results

Description

Computes summary statistics for Monte Carlo simulation results, including the mean estimate, standard error (SE), and confidence intervals (CIs).

Usage

summarize_mc_ci(mc_result, alpha = 0.05)

Arguments

mc_result

A data frame where each column corresponds to a parameter, and each row represents one Monte Carlo replication of that parameter's estimate.

alpha

Numeric. Significance level used to compute the (1 - alpha) confidence interval. Default is 0.05 for a 95% confidence interval.

Value

A data frame with one row per parameter and the following columns:

Parameter

The name of the parameter.

Estimate

The average estimate across all Monte Carlo replications.

SE

The standard deviation of the estimates (standard error).

CI_lower

The lower bound of the confidence interval.

CI_upper

The upper bound of the confidence interval.


Validate user inputs for wsMed()

Description

All checks stop() with an informative message when they fail. Invisibly returns TRUE on success.

Usage

validate_wsMed_inputs(
  data,
  M_C1,
  M_C2,
  Y_C1,
  Y_C2,
  C_C1 = NULL,
  C_C2 = NULL,
  C = NULL,
  W = NULL,
  W_type = NULL,
  MP = NULL,
  form = c("P", "CN", "CP", "PC", "UD"),
  paths = NULL,
  Na = c("DE", "FIML", "MI"),
  R = 20000L,
  bootstrap = 1000L,
  m = 5L,
  ci_level = 0.95,
  ci_method = NULL,
  MCmethod = NULL
)

Analyze two-condition within-subject mediation

Description

wsMed() fits a structural equation model (SEM) for two-condition within-subject mediation. It can handle missing data (DE, FIML, MI) and computes both unstandardized and standardized effects with bootstrap or Monte Carlo confidence intervals.

Usage

wsMed(
  data,
  M_C1,
  M_C2,
  Y_C1,
  Y_C2,
  C_C1 = NULL,
  C_C2 = NULL,
  C = NULL,
  C_type = NULL,
  W = NULL,
  W_type = NULL,
  MP = NULL,
  form = c("P", "CN", "CP", "PC", "UD"),
  Na = c("DE", "FIML", "MI"),
  alpha = 0.05,
  mi_args = list(),
  R = 20000L,
  bootstrap = 2000,
  boot_ci_type = "perc",
  iseed = 123,
  fixed.x = FALSE,
  ci_method = c("mc", "bootstrap", "both"),
  MCmethod = NULL,
  seed = 123,
  standardized = FALSE,
  verbose = FALSE,
  paths = NULL
)

Arguments

data

A data.frame containing the raw scores.

M_C1, M_C2

Character vectors of mediator names under condition 1 and 2.

Y_C1, Y_C2

Character scalars for the outcome under each condition.

C_C1, C_C2

Character vectors of within-subject covariates (per condition).

C

Character vector of between-subject covariates.

C_type

Character; type of C: "continuous" or "categorical".

W

Character vector of moderators. Default NULL.

W_type

Character; "continuous" or "categorical". Automatic numeric 0/1 moderator detection emits a message and is recorded in fit$diagnostics$input_notes. Use an explicit type or factor for consistency with wsmed_fit().

MP

Character vector identifying which regression paths are moderated (for example, "a1", "b_1_2", "cp"). Main effects of W already included in each regression are always used when computing conditional intercepts, whether or not a/cp is explicitly listed in MP.

form

Model type: "P", "CN", "CP", "PC", or "UD". Use "UD" to specify a user-defined mediation model. Values are case-insensitive.

Na

Missing-data method: "DE", "FIML", or "MI". Values are case-insensitive.

alpha

Numeric vector in (0, 1); two-sided significance levels.

mi_args

List of MI-specific controls:

m

Number of imputations. Default 5.

method_num

Imputation method for mice().

completed

Optional list of completed wide data frames or a mice mids object. Observed values, rows and factor levels must be preserved. The number of imputations is inferred; supplied m must match. Omit method_num. With external imputations, seed still controls MC only. See wsmed_fit for model-compatible imputation guidance.

decomposition

Covariance-decomposition method ("eigen", "chol", "svd"). The default "eigen" uses the principal symmetric covariance square root; fixed-seed MI draws differ from wsMed 1.1.0.

pd

Logical; positive-definiteness check.

tol

Tolerance for the positive-definiteness check.

R

Integer; number of Monte Carlo draws. Default 20000L.

bootstrap

Integer; number of bootstrap replicates (DE and FIML only).

boot_ci_type

Character; CI type for stored legacy bootstrap parameter tables: "perc", "bc", or "bca.simple" (zero acceleration). Current effect reports use percentile intervals regardless of this setting.

iseed, seed

Integer seeds for bootstrap and Monte Carlo, respectively.

fixed.x

Logical; passed to lavaan.

ci_method

CI engine: "mc", "bootstrap", or "both". Values are case-insensitive. The default (also used for NULL) is "mc". With Na = "MI", only "mc" is supported.

MCmethod

NULL or "mc". The unimplemented "bootSD" option is rejected explicitly.

standardized

Logical; if TRUE, return standardized parameter tables (including defined effects at the reference moderator value). Raw conditional results remain in moderation; standardized conditional tables and curves are added in moderation_std. Default FALSE. This choice is saved as the default for print, summary, wsmed_effects and generic plot; standardized = TRUE or FALSE on those methods overrides it for one query. Raw fitting parameters remain available through coef and vcov.

verbose

Logical; print progress messages.

paths

A character vector defining directed paths when form = "UD". Paths are specified using mediator labels M1, M2, and so on, with Y denoting the outcome. For example, c("M1 -> M3", "M3 -> Y", "M2 -> Y"). Must be NULL for the predefined model forms.

Details

Model structures:

Missing-data strategies:

Confidence-interval engines:

Monte Carlo inference uses the existing joint-parameter sampler. The legacy MCmethod = "bootSD" option was accepted but never applied; it now produces an explicit error rather than silently returning ordinary MC results.

Standardization divides differences by their marginal model-implied SDs, without recentering them. Dummy variables retain 0/1 units; interaction terms use the product of their component scale factors, not the interaction column SD. MC and bootstrap draws are transformed jointly with their scales. Current effect reports from print, summary and wsmed_effects, and confint applied to extracted effects, use percentile intervals (type-7 quantiles), with or without moderation. The boot_ci_type argument controls stored legacy parameter-table intervals, not these effect reports. In standardized legacy tables, bc and bca.simple apply bias correction with zero acceleration, not full BCa. Their bootstrap p-values require at least 1000 valid replicates.

Conditional tables use percentile intervals and fixed numerical probes. With fixed.x=TRUE, scale transformations condition on the fitted external moments rather than adding sampling uncertainty for those moments. In MI, probes/centering references use the first completed data set; fixed.x=TRUE also conditions on its external moments in the pooled transform. In MI models with products of mediator differences and the moderator, marginal variances are pooled jointly with primitive coefficients, including their delta-method within-imputation and Rubin between-imputation covariance. MC propagates this joint uncertainty. Endogenous product moments are estimated even with fixed.x=TRUE.

Workflow: (1) preprocess -> (2) generate SEM syntax -> (3) fit -> (4) compute confidence intervals -> (5) optional: standardize estimates. See wsmed_categorical for supported categorical predictors, reference coding, and missing-data restrictions. In both interfaces, declare categorical covariates and moderators as unordered factors with explicit levels before fitting. The first factor level is the reference group. Existing automatic recognition of numeric 0/1 predictors is retained in this one-call interface. The empirical manuscript dataset is available as wsmed_examples; example_data is simulated tutorial data.

The one-call interface uses the same fitting and inference engines as wsmed_model(), wsmed_fit(), and wsmed_infer(). Default printing is concise; print(result, detail = "full") adds path coefficients to the structured effect report. Use detail = "legacy" for the original tables. Use wsmed_effects() to query stored draws without rerunning the analysis.

Value

An object of class "wsMed" with elements:

data

Preprocessed data frame.

sem_model

Generated lavaan syntax.

mc

List with Monte Carlo draws, bootstrap tables (if any), and the fitted model.

moderation

Raw conditional or moderated effect tables.

moderation_std

Standardized conditional tables and curves when standardized=TRUE and a moderator is supplied.

form,Na,alpha

Analysis settings.

paths

The user-defined paths when form = "UD"; otherwise NULL.

input_vars

Names of all user-supplied variables.

model,fit,inference

Structured specification, reusable fit (including all imputation fits), and named stored inference objects.

Examples

data("example_data", package = "wsMed")
result <- wsMed(
  data = example_data,
  M_C1 = c("A1", "B1"),
  M_C2 = c("A2", "B2"),
  Y_C1 = "D1",
  Y_C2 = "D2"
)
print(result)


Categorical predictors and supported variable types

Description

wsMed supports binary and multicategory between-subject covariates and one categorical moderator in models with numeric outcomes and mediators.

Supported roles

Outcomes, mediators, and within-subject covariates must be numeric measures analyzed by the continuous-response SEM. Binary or ordinal response models, thresholds, and categorical links are not implemented. Storing a binary outcome as numbers does not turn the estimator into a categorical-response model. Between-subject covariates and the single moderator may instead be unordered factors. Ordered factors are rejected by wsmed_fit(); explicitly convert them to unordered factors only if a nominal interpretation is intended.

Declaring categories

In both the one-call and staged workflows, use base::factor() to declare categorical between-subject covariates and moderators in the input data. Specify levels explicitly: the first level is the reference group. For a binary predictor, factor(x, levels = c(0, 1)) selects 0 as the reference; reversing the levels selects 1. Use unordered factors for nominal categories. Every declared factor level must have observations in the supplied data.

The existing default recognition rules are retained for compatibility. wsmed_fit() treats numeric predictors, including 0/1 columns, as continuous. The one-call wsMed() and PrepareData() interfaces retain automatic detection: factors, character columns, and numeric columns whose observed values are exactly 0 and 1 are categorical. Other numeric columns are continuous unless C_type or W_type overrides detection. Explicit factors provide the same categorical interpretation and reference coding in both interfaces without relying on automatic recognition. The one-call type arguments remain available to override its default rules.

Reference coding and comparisons

A factor with K levels is represented by K - 1 treatment indicators. The first factor level is the reference; stats::relevel() changes it before fitting. Indicators are not mean-centered. Coding does not depend on the global contrasts option. Between-subject indicators use Cb* names and moderator indicators use W* names. The C_info and W_info attributes of prepared data record their mappings. Labels such as low vs high identify the reference and comparison level: the indicator is 0 at low and 1 at high, so its coefficient is high minus low.

wsmed_effects() accepts original factor labels in at; by default it extracts every level. wsmed_contrasts() compares effects using their joint draws, preserving covariance. Do not subtract the endpoints of separate confidence intervals to obtain an interval for a difference. Marginally standardized conditional effects use the common model-implied outcome-difference SD, not separate within-category SDs; factor labels and dummy indicators retain their coding. See standardize_moderation(). Generated models account for the dependence of endogenous products on upstream mediator disturbances. Reference changes preserve the implied marginal scales of the same fitted model. MI pools marginal variance estimates jointly with coefficients; compare the same completed datasets when checking recoding. Refit saved models from before this covariance correction.

Missing values

The staged default missing = "error" rejects missing analysis values. Listwise deletion and multiple imputation are available for incomplete categorical predictors. FIML is allowed with fully observed categorical predictors but wsmed_fit() rejects missing categorical predictors; the one-call interface should follow the same restriction. MI imputes the raw variables before constructing dummy variables and interactions. The staged mi$method argument selects the method for numeric variables (default "pmm"). Factors use logistic regression for two levels and multinomial logistic regression for more than two levels. This differs from the lower-level ImputeData() method argument. MI supports Monte Carlo inference only.

See Also

wsmed_model(), wsmed_fit(), wsmed_effects(), wsmed_contrasts(), PrepareData(), ImputeData()

Examples

data(example_data)
dat <- example_data
dat$Group <- factor(dat$Group, levels = c("low", "med", "high"))
prepared <- PrepareData(dat, M_C1 = "A1", M_C2 = "A2",
                        Y_C1 = "D1", Y_C2 = "D2",
                        W = "Group", W_type = "categorical")
attr(prepared, "W_info")

Contrast effects using their joint stored draws

Description

Contrast effects using their joint stored draws

Usage

wsmed_contrasts(object, contrasts, level = object$query$level)

Arguments

object

A wsmed_results object, containing every effect to compare.

contrasts

Named list of named numeric weight vectors. Weight names must match the term column of as.data.frame(object).

level

Confidence level; defaults to the input result's level.

Value

A wsmed_results object. Intervals are percentile intervals of the jointly evaluated contrasts, not differences between confidence limits.


Extract effects from fitted models or stored inference

Description

Extract effects from fitted models or stored inference

Usage

wsmed_effects(
  object,
  type = c("indirect", "all", "total", "direct", "total_indirect", "paths", "parameters"),
  terms = NULL,
  at = NULL,
  scale = NULL,
  method = NULL,
  level = NULL,
  standardized = NULL
)

Arguments

object

A wsmed_fit, wsmed_inference, or wsMed result.

type

Effect family: indirect, all (direct, specific indirect, total indirect and total effects), total, direct, total_indirect, paths, or parameters (primitive model parameters).

terms

Optional coefficient or effect names within the selected family.

at

Named list of raw moderator values, for example list(Age = c(30, 50)). Defaults to the centering reference for a continuous moderator, or all observed levels for a categorical moderator. Parameters ignore no probes: supplying at with type = "parameters" is an error.

scale

Compatibility spelling: raw or marginal. Explicit conflicting scale and standardized arguments are rejected.

method

Stored inference to use when object is wsMed: mc or bootstrap. Required if both are stored. A fit alone returns point estimates only.

level

Confidence level; defaults to the stored inference level or .95.

standardized

NULL inherits the saved analysis setting (FALSE for older objects without a setting). TRUE uses model-implied marginal endpoint SDs, with or without moderation. FALSE returns raw effects.

Details

Extraction never fits, imputes, or samples. Effect and contrast intervals are percentile intervals from the stored joint draws, including when bootstrap parameter tables were requested with bias correction. For conditional standardization, moderator probes remain fixed in raw units. Scales and coefficients vary jointly across draws. Invalid standardized draws are excluded jointly and their original identities are recorded. For MI the existing first-imputation reference and per-imputation centering are retained. Endogenous products have an auxiliary moment model that retains the necessary upstream residual covariances. MI moderated models jointly pool marginal variances with coefficients, using a delta-method within-imputation covariance and Rubin's rules; MC draws retain their covariance. Refit objects saved before this correction. Finite MC draws or new imputations need not match after recoding. The query interpretation records the plug-in outcome-difference SD. Conditional result tables include extrapolated flags relative to observed moderator values among used participants (imputed values excluded). Out-of-range continuous probes signal wsmed_extrapolation_warning once per extraction; this checks the marginal range, not joint covariate overlap or data density. Categorical tables include n.observed, n.fitted.min, and n.fitted.max; for MI the latter span the completed datasets and are not effective sample sizes. The descriptive support metadata are retained in query$support. Incompatible saved fits stop before extraction. If a fit is compatible but its MI sampler is unversioned or outdated, rerun wsmed_infer() on that fit. Stored primitive coefficients and full legacy tables remain inspectable.

Value

A wsmed_results object with a full-precision table, joint effect draws, draw identities, query settings, and diagnostics.


Data for the manuscript examples

Description

The prepared analysis data used in the three wsMed manuscript examples, derived from the iWeek study deposited by Sagaribay (2025). Each row is one participant; T1 and T2 denote measurements before and after the study period. The examples use T2 minus T1 as the within-person contrast.

Usage

wsmed_examples

Format

A data frame with 123 rows and 14 numeric columns:

TSRQ_T1, TSRQ_T2

Autonomous motivation scores at T1 and T2.

WEMBS_T1, WEMBS_T2

Subjective well-being scores at T1 and T2.

SMUF_T1, SMUF_T2

Daily social media use scores at T1 and T2.

ISI_T1, ISI_T2

Insomnia severity scores at T1 and T2.

DASSS_T1, DASSS_T2

DASS stress-subscale scores at T1 and T2, each calculated as the sum of the seven stress items.

HES_T1, HES_T2

Healthy eating scores at T1 and T2.

Age

Age in years.

BMI

Body mass index, recalculated from weight in pounds and height in inches using 703 * weight / height^2.

Details

Score columns retain their prepared source values without rescaling or standardization. The original dataset contains 221 participants: 123 in the iWeek intervention group and 98 in the control group. This prepared dataset retains the 123 intervention-group participants. The wsMed examples illustrate within-person mediation using their paired T1/T2 measurements; they do not reproduce the original study's group comparison.

The manuscript authors retained the 14 analysis columns and recalculated BMI. Height values outside the preparation rule of 48–84 inches, including ambiguous units, were not converted by guesswork. BMI remains missing for 13 such records. No further participants were removed, no values were imputed, and no additional cleaning is performed when creating this package dataset. SPSS storage attributes are omitted; numerical values, row order, and missing positions match the prepared wsMed_examples.sav replication file.

Across these 14 columns, 55 participants (44.7 percent) have at least one missing value, with 146 missing cells in total. Missing counts for paired T1/T2 columns are TSRQ: 1/22; WEMBS: 0/22; SMUF: 8/18; ISI: 0/19; DASSS: 0/23; HES: 0/20. Age is complete and BMI has 13 missing values. Counts for an individual analysis depend on the variables it selects.

In Examples 1 and 3, TSRQ, WEMBS, and SMUF are mediators; in Example 2, WEMBS and ISI precede TSRQ. DASSS is the outcome, HES is a within-subject covariate, and BMI is a between-subject covariate. Age is a covariate in Examples 1 and 2 and the moderator in Example 3.

The source data and this prepared derivative are distributed under CC BY 4.0, separately from the package code's GPL license. Attribution and modification information are also installed in ‘COPYRIGHTS’.

Source

Sagaribay, R. (2025). iWeek: A Week-Long Social Media Abstinence Intervention and its Impact on Well-Being, Mental Health, Body Image, and Sleep in Latina College Students. Mendeley Data, version 1. doi:10.17632/fn9n95bsh5.1. License: https://creativecommons.org/licenses/by/4.0/.

See Also

example_data(), wsMed(), wsmed_fit()

Examples

data(wsmed_examples)
dim(wsmed_examples)
colSums(is.na(wsmed_examples))
sum(!complete.cases(wsmed_examples))

Fit a specified mediation model without simulation

Description

Fit a specified mediation model without simulation

Usage

wsmed_fit(
  model,
  data,
  missing = c("error", "listwise", "fiml", "mi"),
  mi = list(),
  fixed.x = FALSE,
  verbose = FALSE,
  standardized = FALSE
)

Arguments

model

A wsmed_model object.

data

A wide data frame with one row per participant.

missing

Missing-data strategy: error, listwise, fiml, or mi.

mi

MI controls: m, method, seed, or completed. Supply completed as a list of at least two completed wide data frames or a mice mids object to use externally generated imputations. m is then inferred (or must match). Omit method and seed with completed data. Inference has its own seed.

fixed.x

Whether exogenous moments are fixed in the SEM.

verbose

Show progress messages.

standardized

Logical default for effect extraction, summaries and plots. Does not change model fitting; inference inherits this setting.

Details

This release preserves the existing per-imputation centering and first-imputation reporting reference. It does not implement MI-bootstrap. Factor outcome, mediator, and within-subject covariate columns are unsupported. See wsmed_categorical for reference coding, numeric 0/1 predictors, and restrictions on missing categorical predictors. mi$method specifies the method for numeric variables; factors use logistic or multinomial regression. Default imputation uses main effects and need not preserve substantive-model interactions. For moderated models, consider model-compatible external imputation (e.g., SMC-FCS) and pass its completed datasets. Supplied datasets must preserve participant order, row names, observed values and factor levels, and complete all analysis variables. Difference scores and products are rebuilt separately in every dataset, then the same Rubin/MC engine is used. Validation does not establish imputation-model compatibility. Save the external imputer's settings, convergence diagnostics and software versions separately. Internal MI with moderator interactions signals one wsmed_mi_compatibility_warning per fit and records it in fit diagnostics. Numeric 0/1 moderators remain continuous in this interface; a message explains this choice. For categorical predictors in either interface, use unordered factors with explicit levels; the first level is the reference group. Type messages are retained as diagnostics$input_notes and do not change estimates or random-number state. Diagnostics include dataset-level convergence/admissibility, covariance checks, case counts, warnings, and fitted category counts. Complete-case matrix rank is descriptive, not an identification test for FIML. Counts below five receive a descriptive small-category flag, not a universal validity cutoff. Constant transformed variables are named in pre-fit errors. Non-converged MI datasets stop pooling; known inadmissible fits cannot enter inference.

Value

A wsmed_fit containing all fits and pooled estimates for MI.


Apply uncertainty quantification to an existing fit

Description

Apply uncertainty quantification to an existing fit

Usage

wsmed_infer(
  object,
  method = c("mc", "bootstrap"),
  draws = NULL,
  seed = NULL,
  level = 0.95,
  interval = "perc",
  decomposition = "eigen",
  pd = TRUE,
  tol = 1e-06
)

Arguments

object

A wsmed_fit, or a new wsMed one-call result.

method

mc or bootstrap. MI currently supports mc only.

draws

Number of draws; defaults to 20000 for mc and 2000 for bootstrap.

seed

Random seed, independent of the imputation seed.

level

Confidence level.

interval

Bootstrap interval type: perc, bc, or bca.simple. This controls the legacy parameter table stored in the inference backend. Effect extraction and confint methods always use percentile intervals. bca.simple uses zero acceleration, rather than a full BCa calculation.

decomposition

MI covariance factorization: eigen, chol, or svd.

pd, tol

MI covariance checks; passed to the existing sampler.

Details

Inference never reimputes or changes the supplied fit. Bootstrap necessarily fits resampled datasets. No new statistical engine is introduced. Seeded calls restore the caller's random state; seed = NULL consumes the current random stream and advances it normally. Fits with endogenous products must record compatible model and MI pooling algorithm identifiers. Older unversioned moderated fits require refitting from the original data; package version alone cannot identify their algorithms.

Value

A wsmed_inference storing draws and the original fit.


Inspect a modular workflow without recomputation

Description

Inspect a modular workflow without recomputation

Usage

wsmed_inspect(
  object,
  component = c("model", "syntax", "data", "fits", "diagnostics", "provenance")
)

Arguments

object

A wsmed_model, wsmed_fit, wsmed_inference, or wsMed object.

component

model, syntax, data, fits, diagnostics, or provenance.

Value

The requested specification, syntax, data, backend fits, or metadata.


Methods for modular wsMed objects

Description

Methods for modular wsMed objects

Usage

## S3 method for class 'wsMed'
print(
  x,
  digits = 3,
  detail = c("effects", "full", "overview", "legacy"),
  type = "all",
  at = NULL,
  standardized = NULL,
  method = NULL,
  level = NULL,
  scale = NULL,
  ...
)

## S3 method for class 'wsmed_model'
print(x, ...)

## S3 method for class 'wsmed_fit'
print(x, digits = 3, ...)

## S3 method for class 'wsmed_inference'
print(x, ...)

## S3 method for class 'wsmed_fit'
summary(object, ...)

## S3 method for class 'summary_wsmed_fit'
print(x, digits = 3, ...)

## S3 method for class 'wsmed_inference'
summary(
  object,
  type = "all",
  at = NULL,
  scale = NULL,
  standardized = NULL,
  ...
)

## S3 method for class 'wsMed'
summary(
  object,
  type = "all",
  at = NULL,
  scale = NULL,
  method = NULL,
  standardized = NULL,
  ...
)

## S3 method for class 'wsmed_fit'
coef(object, ...)

## S3 method for class 'wsmed_fit'
vcov(object, ...)

## S3 method for class 'wsmed_fit'
nobs(object, ...)

## S3 method for class 'wsmed_inference'
coef(object, ...)

## S3 method for class 'wsmed_inference'
vcov(object, ...)

## S3 method for class 'wsmed_inference'
nobs(object, ...)

## S3 method for class 'wsMed'
coef(object, ...)

## S3 method for class 'wsMed'
vcov(object, ...)

## S3 method for class 'wsMed'
nobs(object, ...)

## S3 method for class 'wsmed_fit'
confint(object, parm, level = NULL, ...)

## S3 method for class 'wsmed_inference'
confint(object, parm, level = NULL, standardized = NULL, scale = NULL, ...)

## S3 method for class 'wsMed'
confint(
  object,
  parm,
  level = NULL,
  method = NULL,
  standardized = NULL,
  scale = NULL,
  ...
)

## S3 method for class 'wsmed_results'
print(x, digits = 3, ...)

## S3 method for class 'wsmed_results'
summary(object, level = NULL, ...)

## S3 method for class 'wsmed_results'
as.data.frame(x, row.names = NULL, optional = FALSE, ...)

## S3 method for class 'wsmed_results'
coef(object, ...)

## S3 method for class 'wsmed_results'
vcov(object, ...)

## S3 method for class 'wsmed_results'
confint(object, parm, level = NULL, ...)

## S3 method for class 'summary_wsmed'
print(x, digits = 3, ...)

## S3 method for class 'summary_wsmed'
summary(object, level = NULL, ...)

Arguments

x, object

A wsMed or modular workflow object.

digits

Number of displayed digits. Stored estimates are not rounded.

detail

effects (default) for core effects, full for effects and path coefficients, overview for fit status, or legacy for original stored tables.

type, at, scale, method

Passed to wsmed_effects(). Summaries default to all core effects. Select method when both inference engines are stored.

standardized

NULL inherits the saved analysis setting; TRUE or FALSE overrides it without fitting or sampling. Applies with or without moderation.

level

Confidence level. NULL uses the level saved in the selected inference or results object.

...

Additional arguments, passed to effect extraction by summary and confint methods. See wsmed_plots for plotting arguments.

parm

Names or positions of parameters/effects to include in intervals.

row.names, optional

Standard data-frame conversion arguments.

Value

print methods return their input invisibly. summary returns a summary_wsmed (also a wsmed_results) for inference/one-call objects, or a summary_wsmed_fit for fits. Structured summaries contain effects and coefficients data frames, info, diagnostics and selected joint effect draws. as.data.frame, coef, confint, vcov and plot on the summary concern the selected effects; coefficients contains conditional path slopes (not all primitive parameters). Use type = 'parameters' for primitive parameters. Summary display uses printCoefmat; tables retain full precision. coef returns a named numeric vector. vcov returns the fit covariance (Rubin-pooled for MI), or the empirical covariance of stored draws for inference/results. confint recomputes percentile limits from stored draws without sampling. Its default level is the saved level, including when called on an inference or one-call object; use an explicit level to override it. On those two classes confint concerns native primitive parameters, matching coef and vcov regardless of the reporting preference (explicit scale overrides are accepted). Fit-only summaries also describe native parameters. Extract effects first to obtain indirect/conditional-effect intervals. nobs returns the sample size for each fitted dataset. as.data.frame returns a full-precision results table. plot returns a ggplot.

See Also

wsmed_reproducibility() for an exportable analysis manifest.


Specify a two-condition mediation model

Description

Specify a two-condition mediation model

Usage

wsmed_model(
  outcome,
  mediators,
  conditions = names(outcome),
  covariates = list(),
  structure = "parallel",
  paths = NULL,
  moderator = NULL
)

Arguments

outcome

Named pair of outcome columns, in condition order.

mediators

Named list of pairs of mediator columns.

conditions

Two condition names. Defaults to the outcome pair names.

covariates

List with between column names and within named pairs.

structure

One of parallel, serial, serial_parallel, parallel_serial, or custom. Mediator order matters for predefined serial structures.

paths

Directed edges using mediator role names and Y, for custom models.

moderator

NULL or a list with variable, main_effects, interactions, and optionally average_interactions. Only main_effects = "all_equations" is currently supported. Interactions name edges such as "stress -> Y".

Details

All moderator main effects are explicitly included in all difference equations. Difference-slope and average-slope interactions are separate. Categorical between-subject predictors must be unordered factors in the staged workflow. Use the same explicit factor declaration with wsMed(). Set factor levels explicitly; the first level is the reference group.

Value

A wsmed_model specification, without data or fitted estimates.

See Also

wsmed_categorical for supported variable roles and factor coding.


Plot mediation effects from workflow objects

Description

Plot stored effects without fitting, imputing, or drawing new samples. The returned ggplot contains the full-precision plotted table in data.

Usage

## S3 method for class 'wsMed'
plot(
  x,
  type = "indirect",
  terms = NULL,
  at = NULL,
  scale = NULL,
  method = NULL,
  level = NULL,
  view = c("auto", "forest", "curve", "conditional"),
  n = 51L,
  labels = NULL,
  title = NULL,
  x_label = NULL,
  y_label = NULL,
  ncol = NULL,
  base_size = 12,
  rug = FALSE,
  standardized = NULL,
  ...
)

## S3 method for class 'wsmed_inference'
plot(
  x,
  type = "indirect",
  terms = NULL,
  at = NULL,
  scale = NULL,
  method = NULL,
  level = NULL,
  view = c("auto", "forest", "curve", "conditional"),
  n = 51L,
  labels = NULL,
  title = NULL,
  x_label = NULL,
  y_label = NULL,
  ncol = NULL,
  base_size = 12,
  rug = FALSE,
  standardized = NULL,
  ...
)

## S3 method for class 'wsmed_fit'
plot(
  x,
  type = "indirect",
  terms = NULL,
  at = NULL,
  scale = NULL,
  method = NULL,
  level = NULL,
  view = c("auto", "forest", "curve", "conditional"),
  n = 51L,
  labels = NULL,
  title = NULL,
  x_label = NULL,
  y_label = NULL,
  ncol = NULL,
  base_size = 12,
  rug = FALSE,
  standardized = NULL,
  ...
)

## S3 method for class 'wsmed_results'
plot(
  x,
  view = c("auto", "forest", "curve", "conditional"),
  terms = NULL,
  level = NULL,
  labels = NULL,
  title = NULL,
  x_label = NULL,
  y_label = NULL,
  ncol = NULL,
  base_size = 12,
  ...
)

Arguments

x

A wsMed, wsmed_fit, wsmed_inference, or wsmed_results object.

type

Effect family passed to wsmed_effects().

terms

Effect identifiers to select, in display order. For a results object, use either effect identifiers or complete row identifiers.

at

Named list of raw moderator values or factor labels.

scale, method

Passed to wsmed_effects(). Select method explicitly when a one-call object contains both Monte Carlo and bootstrap inference.

level

Confidence level. NULL retains the stored level. For an extracted results object, intervals can be recalculated from its stored effect draws.

view

One of auto, forest, curve, or conditional. Auto uses a curve for a continuous moderator, separate category points for a categorical moderator, and a forest plot for unmoderated effects, single probes, and contrasts.

n

Number of equally spaced probes for an automatic continuous curve (default 51). The range is the finite moderator range among cases used by the first fitted dataset. In MI this is the first completed dataset.

labels

Named character vector mapping effect identifiers to labels. Labels must distinguish effects. Defaults use mediator role names.

title, x_label, y_label

Optional title and axis labels.

ncol

Number of facet columns, or NULL.

base_size

Positive base font size.

rug

Add observed raw moderator values along a continuous curve's horizontal axis. Available for fitted/inference/one-call objects only. Uses fitted cases with an observed moderator; imputed values are excluded.

standardized

NULL inherits the analysis setting; TRUE or FALSE overrides it for this plot. Available on fit, inference and one-call objects.

...

Additional arguments are rejected to catch misspellings.

Details

Curves connect finite probes; bands are pointwise percentile intervals, not simultaneous bands or Johnson–Neyman regions. Supplied probes outside the observed fitted-case range are identified in the caption and plotted data (extrapolated). Group counts appear in categorical captions; for MI these are ranges across completed datasets, not effective sample sizes. Plot metadata retain support, including the observed range or group counts. remain in raw units. A continuous conditional point plot requires explicit at values. Forest plots without at use the usual reference value. Category and effect selections retain their supplied order. A fitted object without inference produces point estimates only, with no confidence band.

Extracted results contain only their selected effects and probes: plotting them never invents a new grid. Use wsmed_effects() again to change the scale, method, or probes. wsmed_contrasts() constructs differences from joint draws. Marginal standardization uses the same draw-specific scales as effect extraction; it does not standardize a plotted table after computing intervals.

The older plot_effects(), plot_conditional_effects(), plot_contrasts(), and plot_moderation_curve() calls remain available. For wsMed objects those helpers preserve the stored legacy tables, including requested bootstrap interval types. The plot methods here use the percentile convention of wsmed_effects(). Plots explicitly identify their interval source.

Value

A ggplot. Its wsmed_plot attribute records the method, scale, confidence level, interval convention, view, and automatic-grid range.

See Also

wsmed_effects(), wsmed_contrasts(), wsmed_methods

Examples

data(example_data)
model <- wsmed_model(c(before = "D1", after = "D2"),
  list(A = c(before = "A1", after = "A2")),
  moderator = list(variable = "D3", interactions = "A -> Y"))
fit <- wsmed_fit(model, example_data)
plot(fit, n = 21, title = "Conditional point estimates")

Export the settings and provenance of an analysis

Description

Export the settings and provenance of an analysis

Usage

wsmed_reproducibility(object, file = NULL)

Arguments

object

A wsmed_model, wsmed_fit, wsmed_inference, wsmed_results, or current wsMed object. A one-call object exports all stored inference methods.

file

Optional new .rds file for the report. Existing files are not overwritten.

Details

This report contains no participant-level data or simulation draws. It is an analysis manifest, not a replacement for the data, analysis script, or a dependency lockfile. It never fits, imputes, samples, or updates results. Recorded fitting versions are separated from the environment used to export. Metadata absent from an older saved object remain absent, not reconstructed from currently installed package versions. Reports for extracted results include the query and contrast definition as well as the upstream settings.

Value

A plain list of model specification, settings, reference coding, diagnostics, and recorded software versions; invisibly when written to file.

Examples

data(example_data)
m <- wsmed_model(c(before = "D1", after = "D2"),
  list(A = c(before = "A1", after = "A2")))
f <- wsmed_fit(m, example_data)
report <- wsmed_reproducibility(f)
report$analysis$missing