Differential Item Function and its Impact on the Differential Test Function Using Item Response Theory Models and Multiple Group Confirmatory Factor Analysis

Abstract

The Current Research Aimed to Identify The Differential Item Function for Watson-Glaser Critical Thinking Test "Short Version" Using Tow Parameter Logistic Model, Nonparametric Smoothing Regression Model and Its Impact on The Differential Test Function by Multiple Group Confirmatory Factor Analysis, The Sample Consisted of 396 Student of Qassim University In KSA (198 Scientific Disciplines, 198 Literary Disciplines), by Using IRTPRO and TestGraf Programs The Following Results Were Reached:

• Many of The Test Item Has Differential Function Favoring The Students Majoring in Scientific Disciplines, and Some of Item Favoring The Students Majoring in Literary Disciplines.
• By Using Multiple Group Confirmatory Factor Analysis, Results Confirmed The Impact of Differential Item Function on The Differential Test Function As A Whole, The Results Interpreted in The Light of The Items Content and The Differences of The Scientific Basis for The Parametric and Nonparametric Item Response Theory Models.