WLErel {TAM}

Reliability Estimation in TAM

Description

Functions for computing reliability estimates.

Usage

WLErel(theta, error, w=rep(1, length(theta)), select=NULL)

EAPrel(theta, error, w=rep(1, length(theta)), select=NULL)

Arguments

theta

Vector with theta estimates

error

Vector with standard errors of theta estimates

w

Optional vector of person weights

select

Optional vector for selecting cases

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).

Value

Numeric value

References

Adams, R. J. (2005). Reliability as a measurement design effect. Studies in Educational Evaluation, 31(2), 162-172. doi:10.1016/j.stueduc.2005.05.008

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)