MODERATING ABILITY OF ITEM RESPONSE THEORY THROUGH PRIOR GUESSING PARAMETER

A psycho-technology approach to discouraging guessing in multiple-choice formatted item can be done through reducing the a priori guessing probability of an item. This study proposes a psychometrics framework of Item Response Theory (IRT) to model the effect of having various priori guessing probabilities across different items. A prior guessing parameter is proposed to serves as a moderator of the ability parameter in the two parameter logistic IRT. The results show that the proposed prior guessing parameter successfully moderates the ability parameters of the subjects with different degrees of guessing. However, the prior guessing parameter is insensitive when the performance pattern is mixed within the testlet but similar across testlet with different priori guessing probabilities.