immer (version 0.4-0)

immer_unique_patterns: Extracts Unique Item Response Patterns

Description

Extracts unique item response patterns.

Usage

immer_unique_patterns(dat, w = rep(1, nrow(dat)))

Arguments

dat

Data frame containing integer item responses

w

Optional vector of weights

Value

• A list with entries
• y
  Data frame with unique item response patterns
• w
  Vector of frequency weights
• y_string
  Item response pattern coded as a string

See Also

See mirt::expand.table for back-converting unique item response patterns into a data frame with item responses.

Examples

#############################################################################
# EXAMPLE 1: Unique item response patterns data.read
#############################################################################

data( data.read , package="sirt")
dat <- data.read

# extract item response patterns
res <- immer_unique_patterns( dat)

# back-conversion with expand.table
dat2 <- mirt::expand.table( cbind( res$y ,  res$w ) )
# check correctness
colMeans(dat)
colMeans(dat2)