Analyzing the Interaction of Item Position Effect and Student Characteristics within Explanatory IRT Models

Abstract

The location of the same item in different positions among booklets leads to a biased estimation of item parameters. This undesirable effect on the probability of answering the items correctly is referred as the item position effect. The purpose of this study is to examine the items that are more sensitive to the item position effect and to investigate the student characteristics related to the item position effect. In the study, the items in the PISA 2015 reading domain are used. The study group consists of 2418 students who responded to the items in the reading domain from PISA 2015 Turkey Sample. Explanatory IRT models are used in the analysis of the research. According to the results, 42% of the items are affected by the item position. The most important characteristic related to item position is the SES level of students. In addition, male students are more affected by item position than female students.