TAM (version 1.995-0)

WLErel: Reliability Estimation in TAM

Description

Functions for computation of reliability estimates.

Usage

WLErel(theta, error, w = rep(1, length(theta)))
EAPrel(theta, error, w = rep(1, length(theta)))

Arguments

theta

Vector with theta estimates

error

Vector with standard errors of theta estimates

w

Optional vector of person weights

Value

Numeric value

Details

The reliability formulas follow Adams (2005). Let $v$ denote the variance of theta estimates and let $s$ denote the average of the squared error. Then, the WLE reliability is defined as $1-s/v=(v-s)/v$ while the EAP reliability is defined as $1 - s/(s+v) = v/(s+v)$.

References

Adams, R. J. (2005). Reliability as a measurement design effect. Studies in Educational Evaluation, 31(2), 162-172.

Examples

#############################################################################
# EXAMPLE 1: Toy example for reliability functions
#############################################################################
	
set.seed(9897)
N <- 100
# simulate theta and error SDs
x <- stats::rnorm(N,sd=2)
error <- stats::runif(N, .7 , 1.3)
# compute WLE reliability
WLErel(x,error)     
# compute EAP reliaility
EAPrel(x,error)