Abstract

• The main purpose of this study is to investigate the level of Diagrammatic Reasoning Skill based on gender and age by using differential item functioning analysis. This study focuses on fairness of the test for everyone. Firstly, Diagrammatic Reasoning Test was developed with the reference of Savillie Diagrammatic Reasoning Test, and Practice Aptitude Tests (Assessment Day). As a pilot test, total 90 items were administered to 115 students from Grade 9 and Grade 11 students from Hlaing Thar Yar Township, Yangon Region on first week of September, 2019. According to the result, 30 good items were selected to develop the Diagrammatic Reasoning Test for the field study. Field study was conducted with 1142 students from Grade 9 and Grade 11 from four districts of Yangon Region. Item Response Theory (IRT) was used to analyze the data. The IRT assumptions of unidimensionality and model-data fitness were checked by using SPSS 22 and BILOG-MG 3.0. And then, parameter estimation was conducted by using Marginal Maximum Likelihood method. After that, DIF analysis was conducted by using Logistic Regression (LG) method and Lord’s Chi-square (LC) method to compare gender and age groups. From the result of gender DIF analysis, it was found that there were four common DIF items for LG and LC methods. According to the result of age DIF analysis, there were only one common DIF items for LG and LC methods.