miceadds: lmer_vcov – R documentation

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lmer_vcov

Statistical Inference for Fixed and Random Structure for Fitted Models in lme4

Description

The function lmer_vcov conducts statistical inference for fixed coefficients and standard deviations and correlations of random effects structure of models fitted in the lme4 package.

The function lmer_pool applies the Rubin formula for inference for fitted lme4 models for multiply imputed datasets.

Usage

lmer_vcov(object, level=.95, use_reml=FALSE, ...)

## S3 method for class 'lmer_vcov'
summary(object, digits=4, file=NULL, ...)
## S3 method for class 'lmer_vcov'
coef(object, ...)
## S3 method for class 'lmer_vcov'
vcov(object, ...)

lmer_vcov2(object, level=.95, ...)

lmer_pool( models, level=.95, ...)
## S3 method for class 'lmer_pool'
summary(object, digits=4, file=NULL, ...)

lmer_pool2( models, level=.95, ...)

Arguments

`object`	Fitted object in lme4
`level`	Confidence level
`use_reml`	Logical indicating whether REML estimates should be used for variance components (if provided)
`digits`	Number of digits used for rounding in summary
`file`	Optional file name for sinking output
`models`	List of models fitted in lme4 for a multiply imputed dataset
`...`	Further arguments to be passed

Value

List with several entries:

`par_summary`	Parameter summary
`coef`	Estimated parameters
`vcov`	Covariance matrix of estimates
`...`	Further values

Author(s)

Function originally from Ben Bolker, http://rpubs.com/bbolker/varwald

Examples

## Not run: 
#############################################################################
# EXAMPLE 1: Single model fitted in lme4
#############################################################################

library(lme4)
data(data.ma01, package="miceadds")
dat <- na.omit(data.ma01)

#* fit multilevel model
formula <- math ~ hisei + miceadds::gm( books, idschool ) + ( 1 + books | idschool )
mod1 <- lme4::lmer( formula, data=dat, REML=FALSE)
summary(mod1)

#* statistical inference
res1 <- miceadds::lmer_vcov( mod1 )
summary(res1)
coef(res1)
vcov(res1)

#############################################################################
# EXAMPLE 2: lme4 model for multiply imputed dataset
#############################################################################

library(lme4)
data(data.ma02, package="miceadds")
datlist <- miceadds::datlist_create(data.ma02)

#** fit lme4 model for all imputed datasets
formula <- math ~ hisei + miceadds::gm( books, idschool ) + ( 1 | idschool )
models <- list()
M <- length(datlist)
for (mm in 1:M){
    models[[mm]] <- lme4::lmer( formula, data=datlist[[mm]], REML=FALSE)
}

#** statistical inference
res1 <- miceadds::lmer_pool(models)
summary(res1)

## End(Not run)

miceadds

Some Additional Multiple Imputation Functions, Especially for 'mice'

v3.11-6

GPL (>= 2)

Authors

Alexander Robitzsch [aut,cre] (<https://orcid.org/0000-0002-8226-3132>), Simon Grund [aut] (<https://orcid.org/0000-0002-1290-8986>), Thorsten Henke [ctb]

Initial release

2021-01-21 11:48:47