sirt: automatic.recode – R documentation

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automatic.recode

Automatic Method of Finding Keys in a Dataset with Raw Item Responses

Description

This function calculates keys of a dataset with raw item responses. It starts with setting the most frequent category of an item to 1. Then, in each iteration keys are changed such that the highest item discrimination is found.

Usage

automatic.recode(data, exclude=NULL, pstart.min=0.6, allocate=200,
    maxiter=20, progress=TRUE)

Arguments

`data`	Dataset with raw item responses
`exclude`	Vector with categories to be excluded for searching the key
`pstart.min`	Minimum probability for an initial solution of keys.
`allocate`	Maximum number of categories per item. This argument is used in the function `tam.ctt3` of the TAM package.
`maxiter`	Maximum number of iterations
`progress`	A logical which indicates if iteration progress should be displayed

Value

A list with following entries

`item.stat`	Data frame with item name, p value, item discrimination and the calculated key
`data.scored`	Scored data frame using calculated keys in `item.stat`
`categ.stats`	Data frame with statistics for all categories of all items

Examples

## Not run: 
#############################################################################
# EXAMPLE 1: data.raw1
#############################################################################
data(data.raw1)

# recode data.raw1 and exclude keys 8 and 9 (missing codes) and
# start with initially setting all categories larger than 50 
res1 <- sirt::automatic.recode( data.raw1, exclude=c(8,9), pstart.min=.50 )
# inspect calculated keys
res1$item.stat

#############################################################################
# EXAMPLE 2: data.timssAusTwn from TAM package
#############################################################################

miceadds::library_install("TAM")
data(data.timssAusTwn,package="TAM")
raw.resp <- data.timssAusTwn[,1:11]
res2 <- sirt::automatic.recode( data=raw.resp )

## End(Not run)

sirt

Supplementary Item Response Theory Models

v3.10-118

GPL (>= 2)

Authors

Alexander Robitzsch [aut,cre] (<https://orcid.org/0000-0002-8226-3132>)

Initial release

2021-09-22 17:45:34