The Effects of Distractors to Differential Item Functioning in Peabody Picture Vocabulary Test

In this study logistic regression and Lord's Chi Square methods were used to research the items that have DIF. The study utilized Peabody Picture Vocabulary Test (PPVT). The original form of the PPVT includes four options. Three different forms (A, B and C) were formed by removing one of the distractors respectively. The original form of PPVT was implemented in a group of 970 preschool children who were aged between 3 to 6. 757 of them took one of the forms. In each implementation, the order to the implementation of the original form and the form (A, B or C) was changed. The applications were conducted 15 days apart. In the first application, the original form was applied, while one of the devised forms (A, B or C) was used in the following application. In this way, the effect of order of application on responses was investigated. The gender variable constituted the reference and focus group of the study. The Logistic Regression and Lord's Chi-square methods did not give compatible results in DIF analysis. DIF was found in 15 items in the original form according to the logistic regression method and in nine items according to the Lord's Chi-square method. The three-option and four-option applications of the test revealed that DIF was determined in five items in different forms. It was observed that there was no compliance in different applications and analyses in other items with DIF.