lavaan — cfa.extract.itempars" />
cfa
Object in lavaancfa.extract.itempars.Rd
This function extract item parameters from a fitted
lavaan::cfa
object in lavaan. It
extract item loadings, item intercepts and the mean
and covariance matrix of latent variables in a
confirmatory factor analysis model.
cfa.extract.itempars(object)
object | Fitted |
---|
List with following entries
Matrix of item loadings
Vector of item intercepts
Residual covariance matrix
Covariance matrix of latent variables
Vector of means of latent variables
Further values
See IRTLikelihood.cfa
for extracting the
individual likelihood from fitted confirmatory
factor analyses.
############################################################################# # EXAMPLE 1: CFA data.Students ############################################################################# library(lavaan) library(CDM) data(data.Students, package="CDM") dat <- data.Students dat1 <- dat[, paste0( "mj", 1:4 ) ] #*** Model 1: Unidimensional model scale mj lavmodel <- " mj=~ mj1 + mj2 + mj3 + mj4 mj ~~ mj " mod1 <- lavaan::cfa( lavmodel, data=dat1, std.lv=TRUE ) summary(mod1, standardized=TRUE, rsquare=TRUE ) # extract parameters res1 <- TAM::cfa.extract.itempars( mod1 ) if (FALSE) { #*** Model 2: Scale mj - explicit modelling of item intercepts lavmodel <- " mj=~ mj1 + mj2 + mj3 + mj4 mj ~~ mj mj1 ~ 1 " mod2 <- lavaan::cfa( lavmodel, data=dat1, std.lv=TRUE ) summary(mod2, standardized=TRUE, rsquare=TRUE ) res2 <- TAM::cfa.extract.itempars( mod2 ) #*** Model 3: Tau-parallel measurements scale mj lavmodel <- " mj=~ a*mj1 + a*mj2 + a*mj3 + a*mj4 mj ~~ 1*mj mj1 ~ b*1 mj2 ~ b*1 mj3 ~ b*1 mj4 ~ b*1 " mod3 <- lavaan::cfa( lavmodel, data=dat1, std.lv=TRUE ) summary(mod3, standardized=TRUE, rsquare=TRUE ) res3 <- TAM::cfa.extract.itempars( mod3 ) #*** Model 4: Two-dimensional CFA with scales mj and sc dat2 <- dat[, c(paste0("mj",1:4), paste0("sc",1:4)) ] # lavaan model with shortage "__" operator lavmodel <- " mj=~ mj1__mj4 sc=~ sc1__sc4 mj ~~ sc mj ~~ 1*mj sc ~~ 1*sc " lavmodel <- TAM::lavaanify.IRT( lavmodel, data=dat2 )$lavaan.syntax cat(lavmodel) mod4 <- lavaan::cfa( lavmodel, data=dat2, std.lv=TRUE ) summary(mod4, standardized=TRUE, rsquare=TRUE ) res4 <- TAM::cfa.extract.itempars( mod4 ) }