Estimating Item Characteristic Curves

Abstract

A simulation study of the effectiveness of four item characteristic curve estimation programs was conducted. Using the three-parameter logistic model, three groups of 2,000 simulated subjects were administered 80-item tests. These simulated test responses were then calibrated using the four programs. The estimated item parameters were compared to the known item parameters in four analyses for each program in all three data sets. It was concluded that the selection of an item calibra tion procedure should be dependent on the distri bution of ability in the calibration sample, the later uses of the item parameters, and the computer re sources available.