get_surrogates {flexmet}

Find Theta Surrogates

Description

Compute surrogate theta values as the set of normalized first principal component scores.

Usage

get_surrogates(dat)

Arguments

dat

Matrix of binary item responses.

Details

Compute surrogate theta values as the normalized first principal component scores.

Value

Vector of surrogate theta values.

References

Liang, L., & Browne, M. W. (2015). A quasi-parametric method for fitting flexible item response functions. Journal of Educational and Behavioral Statistics, 40, 5–34. doi: 10.3102/1076998614556816

Examples

set.seed(2342)
bmat <- sim_bmat(n_items = 5, k = 2)$bmat

theta <- rnorm(50)
dat <- sim_data(bmat = bmat, theta = theta)

tsur <- get_surrogates(dat)