Studies have shown that item difficulty can vary significantly based on the context of an item within a test form. In particular, item position may be associated with practice and fatigue effects that influence item parameter estimation. The purpose of this research was to examine the relevance of item position specifically for assessments used in…

K-12 intervention studies often include fidelity of implementation (FOI) as a mediating variable, though most do not report the validity of fidelity measures. This article discusses the critical need for validated FOI scales. To illustrate our point, we describe the development and validation of the Implementation Validity Checklist (IVC-R), an…

This study demonstrated the equivalence between the Rasch testlet model and the three-level one-parameter testlet model and explored the Markov Chain Monte Carlo (MCMC) method for model parameter estimation in WINBUGS. The estimation accuracy from the MCMC method was compared with those from the marginalized maximum likelihood estimation (MMLE)…