In jsakaluk/dySEM: Dyadic Structural Equation Modeling

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dySEM

Summary

The dySEM helps automate the process of scripting, fitting, and reporting on latent models of dyadic data via lavaan. The package was developed and used in the course of the research described in Sakaluk, Fisher, & Kilshaw (2021).

The dySEM logo was designed by Lowell Deranleau (for logo design inquiries, email: agangofwolves@gmail.com).

Installation

You can install the released version of dySEM from CRAN with:

install.packages("dySEM")

You can install the development version from GitHub with:

``` {r, eval = FALSE}

install.packages("devtools")

devtools::install_github("jsakaluk/dySEM")

## Current Functionality 

The package currently provides functionality regarding the following types of latent dyadic data models: 

1. **Dyadic Confirmatory Factor Analysis** 
1. **Latent Actor-Partner Interdependence Models (APIM)**
1. **Latent Common Fate Models (CFM)**
1. **Latent Bifactor Dyadic (Bi-Dy) Models**
1. **Observed Actor-Partner Interdependence (APIM)**

Additional features currently include:

* Automated specification of invariance constraints for any model, including full indistinguishability
* Functions to assist with the specification of **I-SAT Models** and **I-NULL Models** for calibrated model fit indexes with indistinguishable dyad models
* Functions to assist with reproducible creation of path diagrams and tables of statistical output
* Functions to calculate supplemental statistical information (e.g., omega reliability, noninvariance effect sizes, corrected model fit indexes)

## Future Functionality

Functionality targeted for future development of `dySEM` is tracked [here](https://github.com/jsakaluk/dySEM/projects/1). Current high-priority items include: 

1. Longitudinal dyadic model scripting functions (e.g., curve of factors, common fate growth)
1. Latent dyadic response surface analysis scripting and visualization functions
1. Multi-group dyadic model scripting (e.g., comparing models from samples of heterosexual vs. LGBTQ+ dyads) 
1. Covariate scripting and optionality
1. Improved ease of item selection in scraper functions

## Collaboration

Please submit any feature requests via the `dySEM` [issues](https://github.com/jsakaluk/dySEM/issues) page, using the "Wishlist for dySEM Package Development" tag. 

If you are interested in collaborating on the development of `dySEM`, please contact Dr. Sakaluk.

## dySEM Workflow

A `dySEM` workflow typically involves five steps, which are covered in-depth in the [Overview vignette](https://jsakaluk.github.io/dySEM/articles/dySEM.html). Briefly, these steps include:

1. Import and wrangle **data**
1. **Scrape** variables from your data frame
1. **Script** your preferred model
1. **Fit** and **Inspect** your model via `lavaan`
1. **Output** statistical visualizations and/or tables 

There are additional optional functions, as well, that help users to calculate certain additional quantitative values (e.g., reliability, corrected model fit indexes in models with indistinguishable dyad members). 

```r
library(dySEM)
library(tidyverse)
library(lavaan)
DRES <- as_tibble(select(DRES, PRQC_1.1:PRQC_9.2))

1. Import and wrangle data

Structural equation modeling (SEM) programs like lavaan require dyadic data to be in dyad structure data set, whereby each row contains the data for one dyad, with separate columns for each observation made for each member of the dyad. For example:

DRES

2. Scrape variables from your data frame

The dySEM scrapers consider appropriately repetitiously named indicators as consisting of at least three distinct elements: stem, item, and partner. Delimiter characters (e.g., “.”, "_") are commonly–but not always–used to separate some/all of these elements.dySEM scrapers largely function by asking you to specify in what order the elements of variable names are ordered.

dvn <- scrapeVarCross(DRES, x_order = "sip", x_stem = "PRQC", x_delim1="_",x_delim2=".",  distinguish_1="1", distinguish_2="2")

3. Script your preferred model

Scripter functions like scriptCFA typically require only three arguments to be specified:

the dvn object (e.g., from scrapeVarCross) to be used to script the model 1.arbitrary name(s) for the latent variable(s) you are modeling
the kind of parameter equality constraints that you wish to be imposed (if any)

qual.indist.script <- scriptCFA(dvn, lvname = "Quality")

This function returns a character object with lavaan compliant syntax for your chosen model, as well as exporting a reproducible .txt of the scripted model to a /scripts folder in your working directory.

4. Fit and Inspect your model via `lavaan`

You can immediately pass any script(s) returned from a dySEM scripter to your preferred lavaan wrapper, with your estimator and missing data treatment of choice. For example:

qual.indist.fit <- lavaan::cfa(qual.indist.script, data = DRES, std.lv = FALSE, auto.fix.first= FALSE, meanstructure = TRUE)

At this point, the full arsenal of lavaan model-inspecting tools are at your disposal. For example:

summary(qual.indist.fit, fit.measures = TRUE, standardized = TRUE, rsquare = TRUE)

5. Output statistical visualizations and/or tables

dySEM also contains functionality to help you quickly, correctly, and reproducibly generate output from your fitted model(s), in the forms of path diagrams and/or tables of statistical values. By default these save to a temporary directory, but you can specify a directory of your choice by replacing tempdir() (e.g., with ".", which will place it in your current working directory).

outputModel(dvn, model = "cfa", fit = qual.indist.fit, 
            table = TRUE, tabletype = "measurement", 
            figure = TRUE, figtype = "unstandardized",
            writeTo = tempdir(),
            fileName = "dCFA_indist")