AN EVALUATION OF THE TWO PARAMETER (2-PL) IRT MODELS THROUGH A SIMULATION STUDY

Abstract

Our aim is to evaluate parameter estimation of two parameters item response theory (2-PL IRT) model using Joint Maximum Likelihood (JML). A simulation study is approached in terms of different sample sizes, number of items and levels of ability parameters for different level of discirimination parameter. As a result of this simulation study examinee ability parameter, item discrimination and difficulty parameters are obtained as well as Test Information Function and Point-biserial Correlation. One of the highlighted results shows that the level of discrimination parameter plays an important role in parameter estimation for 2-PL IRT models.