Compare Nested and Non-Nested Structural Equation Models R package modelscompete4 version 0.2.6 A comprehensive package for comparing multiple Structural Equation Models (SEM). Supports both nested and non-nested model comparisons, chi-square difference tests, and extraction of multiple fit indices including AIC (Akaike Information Criterion), BIC (Bayesian Information Criterion), CFI (Comparative Fit Index), TLI (Tucker-Lewis Index), RMSEA (Root Mean Square Error of Approximation), and SRMR (Standardized Root Mean Square Residual). Built on top of the 'lavaan' package for seamless SEM model comparison workflows. The Vuong test (Vuong, 1989) for non-nested models is used as the statistical test. Software Imports: lavaan (>= 0.6), stats, boot, ggplot2, nonnest2, tidyr Suggests: testthat (>= 3.0.0) Jerf Yeung <ssjerf@gmail.com> Comprehensive R Archive Network (CRAN) Jerf Yeung [aut, cre] GPL (>= 3) 2026-04-24 application/tgz https://CRAN.R-project.org/package=modelscompete4 doi:10.32614/CRAN.package.modelscompete4