Master thesis | Statistical Science for the Life and Behavioural Sciences (MSc)
open access
We propose a varying coefficient IRT model, in order to study the effect of a metric variable on model and population parameters estimated by IRT models. Kernel smoothing was used to capture the...Show moreWe propose a varying coefficient IRT model, in order to study the effect of a metric variable on model and population parameters estimated by IRT models. Kernel smoothing was used to capture the variation, and cross-validation to determine optimal parameters. The model was applied to a variety of simulated data sets in order to test its properties, and on a real-world personality data set. The tests on simulated data showed the ability to recover and visualize the variation of coefficients and their confidence bands over time with some success. The real-world tests showed some, but limited variation, depending on the trait studied.Show less
