Optimal Testing With Easy or Difficult Items in Computerized Adaptive Testing

In the present study it is shown that maximum information item selection in CATs using an item bank which is calibrated with the one- or the two-parameter logistic model, results in each individual answering about 50% of the items correctly. Two item selection procedures giving easier (or more difficult) tests for students are presented and evaluated. Item selection on probability points of items yields good results only with the 1 pl model and not with the 2pl model. An alternative selection procedure, based on maximum information at a shifted ability level, gives satisfactory results with both models.