A comparison between the one and three parameter logistic approaches in estimating item difficulty and person ability under simulated conditions

الملخص EN

The purpose of this study was to compare between the one and three parameter logistic approaches in estimating item difficulty and person ability.

To achieve this goal, simulated conditions of different sample sizes (40, 80, and 600 persons) and test length of (30 and 60 items) were used.

This data was fitted in the one-parameter and three-parameter logistic models using the BILOG program to estimate person ability and item parameters.

The results indicated that, there is a significant effect of number of items on the difficulty and ability estimates concerning Rasch model, and the effect of number of subjects and its interaction with number of items are significant regarding the three-parameter model for both of item difficulty and person ability