The Effect of Interaction Between the Item Parameters and Ability Levels on the Item Information Function in the Two-Parameter Logistic model

Abstract

This study aimed to identify the effect of interaction between item parameters, and interaction between item parameters and ability levels, on the Item information function in the two-parameter logistic model. WINGEN was used to generate (6000)responses tested on (600) items. BILOGM and SPSS were used in the analysis. The analyzed results showed that there were statistically significant differences in the item information function mean due to the interaction between difficulty and discrimination. More, the results indicated that the mean of the item information function increased by increasing the item discrimination. The highest value of the item information function mean was achieved when the intermediate level of difficulty and high level of discrimination. Also, the results showed that there were statistically significant differences in the item information function mean due to the interaction between item parameters and ability levels. It was observed that the item information function increases as the levels of ability and difficulty are close, and the level of discrimination increases. The highest value of the item information function was achieved when high levels of ability, difficulty and discrimination interacted.