emreliability (version 1.0.0)

csem_lord_keats: CSEM: Lord Keats Method

Description

Compute CSEM using the Lord Keats approach, which rescales Lord's binomial-model CSEM using empirical KR-20 and KR-21 reliability estimates.

Usage

csem_lord_keats(x)

Value

A list with:

x

Vector of raw scores from 0 to ni.

csem

Vector of CSEM values under the Lord Keats method.

Arguments

x

A data frame or matrix of item responses, with rows as persons and columns as items. Items are assumed to be dichotomous (0/1).

Details

This function first computes Lord's CSEM under the binomial model via csem_lord(ni), where ni = ncol(x). It then rescales the resulting CSEM curve using the ratio $$ \sqrt{\frac{1 - \text{KR-20}}{1 - \text{KR-21}}}, $$ where KR-20 and KR-21 are computed from the observed data via kr20(x) and kr21(x), respectively.

Examples

data(data.u)
csem_lord_keats(data.u)