Comparison of Different Ability Estimation Methods Based on 3 and 4PL Item Response Theory

Abstract

This research analyzed the two-category Item Response Theory (IRT) models as part of different ability estimation methods. The research was carried out in consideration of responses to 20 items under the Mathematics subtest of TEOG (National Transition from Primary to Secondary Education) exam by the 8th-grade students in 2015-2016. The study group consisted of 400 students who were randomly selected from the students participated in the TEOG exam. Ability estimations and standard error values for these estimations were calculated based on the data. These estimations were compared by two-way analysis of variance (ANOVA) for repeated measurements According to the research findings; it was revealed that the four-parameter logistic (4PL) item model fit better. In terms of ability estimation methods, the accuracy of Weighted Likelihood Estimation (WLE) was higher than Maximum A Posteriori (MAP) and Expected A Posteriori (EAP). WLE and MAP ability estimation model gave lower standard error values compared to the 4PL and 3PL model, respectively. The highest marginal reliability coefficient value for the 3PL model was calculated using estimations made according to MAP while estimations made according to WLE were used for the 4PL model. According to the research findings, it was concluded that the accuracy of ability scores obtained by the WLE estimation method under the 4PL model was higher.