Ability Estimation with Polytomous Items in Computerized Multistage Tests

The aim of the study is to examine how the ability estimations of individuals change under different conditions in tests consisting of polytomous items in an computerized multistage test environment. The research is a simulation study. In the study, 108 (3x3x6x2=108) conditions were examined consisting of three categories (3, 4 and 5), three test lengths (10, 20 and 30), six panel designs (1-2, 1-2-2, 1-3, 1-3-3, 1-4 and 1-4-4) and two routing methods (Maximum Fisher Information (MFI) and Random). Simulations and analyses were carried out in the mstR package in R program, with a pool of 200 items, 1000 people and 100 replications (e.g., iterations). As the outcomes of the research, mean absolute bias, RMSE and correlation values were calculated. It was found that as the number of categories and test length increase, the mean absolute bias and RMSE values decrease, while the correlation values increase. In terms of routing methods, although MFI and random methods have similar tendencies, MFI gives better results. There is a similarity between the panel designs in terms of results.