item_by_group: Create Dataset with Group-Specific Items

In CDM: Cognitive Diagnosis Modeling

Create Dataset with Group-Specific Items

Description

Creates a dataset with group-specific items which can be used for multiple group comparisons.

Usage

item_by_group(dat, group, invariant=NULL, rm.empty=TRUE)

Arguments

dat	Dataset with item responses
group	Vector of group identifiers
invariant	Optional vector of variables which should not be made group-specific, i.e. which should be treated as invariant across groups.
rm.empty	Logical indicating whether empty columns should be removed

Value

Extended dataset with item responses

Examples

## Not run: 
#############################################################################
# EXAMPLE 1: Create dataset with group-specific item responses
#############################################################################

data(data.mg, package="CDM")
dat <- data.mg

#-- create dataset with group-specific item responses
dat0 <- CDM::item_by_group( dat=dat[,paste0("I",1:5)], group=dat$group )

#-- summary statistics
summary(dat0)
colnames(dat0)

#-- set some items to invariant
invariant_items <- c("I1","I4")
dat1 <- CDM::item_by_group( dat=dat[,paste0("I",1:5)], group=dat$group,
            invariant=invariant_items)
colnames(dat1)

## End(Not run)

CDM documentation built on Aug. 25, 2022, 5:08 p.m.