The aim of the study is to examine the effect of polytomous item ratio on ability estimation in different conditions in multistage tests (MST) using mixed tests. The study is simulation-based research. In the PISA 2018 application, the ability parameters of the individuals and the item pool were created by using the item parameters estimated from…

Testlets have advantages such as making it possible to measure higher-order thinking skills and saving time, which are accepted in the literature. For this reason, they have often been preferred in many implementations from in-class assessments to large-scale assessments. Because of increased usage of testlets, the following questions are…