Item Parameter Estimation for Dichotomous Items Based on Item Response Theory: Comparison of BILOG-MG, Mplus and R (ltm)

Abstract

The aim of this study is twofold. The first one is to investigate the effect of sample size and test length on theestimation of item parameters and their standard errors for the two parameter item response theory (IRT). Anotheris to provide information about the performance of Mplus, BILOG-MG and R (ltm) programs in terms of parameterestimation under the conditions which were mentioned above. The simulated data were used in this study. Theexaminee responses were generated by using the open-source program R. After obtaining the data sets, theparameters were estimated in BILOG-MG, Mplus and R (ltm). The accuracy of the item parameters and abilityestimates were evaluated under six conditions that differed in the numbers of items and examinees. After lookingat the resulting bias and root mean square error (RMSE) values, it can be concluded that Mplus is an unbiasedprogram when compared to BILOG-MG and R (ltm). BILOG-MG can estimate parameters and standard errorsclose to the true values, when compared to Mplus and R (ltm)