% Generated by roxygen2: do not edit by hand
% Please edit documentation in R/model_performance.lavaan.R
\name{model_performance.lavaan}
\alias{model_performance.lavaan}
\title{Performance of lavaan SEM / CFA Models}
\usage{
\method{model_performance}{lavaan}(model, metrics = "all", verbose = TRUE, ...)
}
\arguments{
\item{model}{A \strong{lavaan} model.}

\item{metrics}{Can be \code{"all"} or a character vector of metrics to be
computed (some of \code{"Chi2"}, \code{"Chi2_df"}, \code{"p_Chi2"}, \code{"Baseline"},
\code{"Baseline_df"}, \code{"p_Baseline"}, \code{"GFI"}, \code{"AGFI"}, \code{"NFI"}, \code{"NNFI"},
\code{"CFI"}, \code{"RMSEA"}, \code{"RMSEA_CI_low"}, \code{"RMSEA_CI_high"}, \code{"p_RMSEA"},
\code{"RMR"}, \code{"SRMR"}, \code{"RFI"}, \code{"PNFI"}, \code{"IFI"}, \code{"RNI"}, \code{"Loglikelihood"},
\code{"AIC"}, \code{"BIC"}, and \code{"BIC_adjusted"}.}

\item{verbose}{Toggle off warnings.}

\item{...}{Arguments passed to or from other methods.}
}
\value{
A data frame (with one row) and one column per "index" (see
\code{metrics}).
}
\description{
Compute indices of model performance for SEM or CFA models from the
\strong{lavaan} package.
}
\details{
\subsection{Indices of fit}{
\itemize{
\item \strong{Chisq}: The model Chi-squared assesses overall fit and the
discrepancy between the sample and fitted covariance matrices. Its p-value
should be > .05 (i.e., the hypothesis of a perfect fit cannot be
rejected). However, it is quite sensitive to sample size.
\item \strong{GFI/AGFI}: The (Adjusted) Goodness of Fit is the proportion
of variance accounted for by the estimated population covariance.
Analogous to R2. The GFI and the AGFI should be > .95 and > .90,
respectively.
\item \strong{NFI/NNFI/TLI}: The (Non) Normed Fit Index. An NFI of 0.95,
indicates the model of interest improves the fit by 95\\% relative to the
null model. The NNFI (also called the Tucker Lewis index; TLI) is
preferable for smaller samples. They should be > .90 (Byrne, 1994) or >
.95 (Schumacker and Lomax, 2004).
\item \strong{CFI}: The Comparative Fit Index is a revised form of NFI.
Not very sensitive to sample size (Fan, Thompson, and Wang, 1999). Compares
the fit of a target model to the fit of an independent, or null, model. It
should be > .90.
\item \strong{RMSEA}: The Root Mean Square Error of Approximation is a
parsimony-adjusted index. Values closer to 0 represent a good fit. It
should be < .08 or < .05. The p-value printed with it tests the hypothesis
that RMSEA is less than or equal to .05 (a cutoff sometimes used for good
fit), and thus should be not significant.
\item \strong{RMR/SRMR}: the (Standardized) Root Mean Square Residual
represents the square-root of the difference between the residuals of the
sample covariance matrix and the hypothesized model. As the RMR can be
sometimes hard to interpret, better to use SRMR. Should be < .08.
\item \strong{RFI}: the Relative Fit Index, also known as RHO1, is not
guaranteed to vary from 0 to 1. However, RFI close to 1 indicates a good
fit.
\item \strong{IFI}: the Incremental Fit Index (IFI) adjusts the Normed Fit
Index (NFI) for sample size and degrees of freedom (Bollen's, 1989). Over
0.90 is a good fit, but the index can exceed 1.
\item \strong{PNFI}: the Parsimony-Adjusted Measures Index. There is no
commonly agreed-upon cutoff value for an acceptable model for this index.
Should be > 0.50. }
}

See the documentation for \code{?lavaan::fitmeasures}.

\subsection{What to report}{
Kline (2015) suggests that at a minimum the following indices should be
reported: The model \strong{chi-square}, the \strong{RMSEA}, the \strong{CFI}
and the \strong{SRMR}.
}
}
\examples{
\dontshow{if (require("lavaan")) (if (getRversion() >= "3.4") withAutoprint else force)(\{ # examplesIf}
# Confirmatory Factor Analysis (CFA) ---------
data(HolzingerSwineford1939, package = "lavaan")
structure <- " visual  =~ x1 + x2 + x3
               textual =~ x4 + x5 + x6
               speed   =~ x7 + x8 + x9 "
model <- lavaan::cfa(structure, data = HolzingerSwineford1939)
model_performance(model)
\dontshow{\}) # examplesIf}
}
\references{
\itemize{
\item Byrne, B. M. (1994). Structural equation modeling with EQS and
EQS/Windows. Thousand Oaks, CA: Sage Publications.
\item Tucker, L. R., and Lewis, C. (1973). The reliability coefficient for
maximum likelihood factor analysis. Psychometrika, 38, 1-10.
\item Schumacker, R. E., and Lomax, R. G. (2004). A beginner's guide to
structural equation modeling, Second edition. Mahwah, NJ: Lawrence Erlbaum
Associates.
\item Fan, X., B. Thompson, and L. Wang (1999). Effects of sample size,
estimation method, and model specification on structural equation modeling
fit indexes. Structural Equation Modeling, 6, 56-83.
\item Kline, R. B. (2015). Principles and practice of structural equation
modeling. Guilford publications.
}
}
