Nicolai D. Ayasse, Cheryl D. Coon
Purpose
Item response theory (IRT) models are an increasingly popular method choice for evaluating clinical outcome assessments (COAs) for use in clinical trials. Given common constraints in clinical trial design, such as limits on sample size and assessment lengths, the current study aimed to examine the appropriateness of commonly used polytomous IRT models, specifically the graded response model (GRM) and partial credit model (PCM), in the context of how they are frequently used for psychometric evaluation of COAs in clinical trials.