simEquiTable: Computes equivalence table for the Rasch model

In weirichs/eatModel: Educational Assessment Tools for IRT Modeling using Conquest or TAM

Computes equivalence table for the Rasch model

Description

Function provides the equivalence table for unidimensional 1pl models, specifying the individual competence level for each possible total score of the test.

Usage

simEquiTable  ( anchor, mRef, sdRef, addConst = 500, multConst = 100, 
cutScores )

Arguments

anchor	A data frame with anchor parameters on the logit scale, transformed to the metric of the reference population. The first column contains the names of all anchored items. The second column contains anchor parameters.
mRef	Scalar: mean of the reference population.
sdRef	Scalar: Standard deviation of the reference population.
addConst	Additive constant for parameter transformation.
multConst	Multiplicative constant for parameter transformation.
cutScores	Named list of one or two elements. "values" is a numeric vector of cut scores (increasing), "labels" is an optional character vector of cut score labels. Note that "labels" (if specified) has to be of one more length than "values".

Value

A list of two data frames, including the complete table and the reduced table with the following 5 columns.

score

Students raw score

est

Estimated individual WLE according to the raw score.

bista

Transformed WLE

ks

competence level

Author(s)

Johannes Schult

Examples

# read anchor parameter
file <- system.file("extdata", "results.rda", package = "eatModel")
load(file)

# use domain 'reading'
prm  <- subset(itemFromRes(res), model == "komplesen")

# use bista cut scores
cuts   <- list ( values = 390+0:3*75, labels = c("I", "II", "III", "IV", "V") )

# create the equivalence table
ret <- simEquiTable( anchor = prm[,c("item", "est")], cutScores = cuts , mRef = 0.039, sdRef = 1.071)

weirichs/eatModel documentation built on Jan. 26, 2025, 4:01 p.m.