reliabiltyFS {ThurMod}

Calculate reliability estimate for factor scores.

Description

This function returns a reliability estimate for factor scores estimated via the Thurstonian IRT models.

Usage

reliabiltyFS(scores, scores_se, method = "sub")

Arguments

scores

A matrix with factor scores. Rows are respondents, columns are factors/traits.

scores_se

A matrix with the standard errors of the factor scores. Rows are respondents, columns are factors/traits. Factors/traits must be in the same order as for 'scores'.

method

Can be one of 'div' or 'sub'. See details. Defaults to 'sub'.

Details

The function returns the empirical reliability of factor scores. If \sigma^2 is the sample variance of the estimated scores and \bar{sigma}^2_{error} is the average if the squared scores, that is

\bar{sigma}^2_{error}=\frac{1}{N}\sum^N_i=1 se_{scores}^2

then the subtraction method, a classical reliability estimate similar to classical test theory is returned using 'sub' yields

\frac{\sigma^2-\bar{sigma}^2_{error}}{\sigma^2}

for the reliability of the scores. If 'div' is chosen, and alternative division based approach is used.

\frac{\sigma^2}{\sigma^2+\bar{sigma}^2_{error}}

.

If 'irt' is chosen, a plot returning the standard error of the scores with the scores is returned per factor.

Value

Returns the reliability value. If method = 'irt', the a plot with the reliability depending on the factorscore is returned.

Examples

# read and save data set FC
data(FC_scores)

# get reliability
reliabiltyFS(FC_scores[,c(106,108,110)],FC_scores[,c(107,109,111)])