A test of 24 students by 24 questions was scored with Ministep and with Power Up Plus (PUP). Passing was 75% on this nursing school test.
Winsteps prints out identical data in Table 17.1 Person Statistics. Student names are even listed in the same order for students with the same score.
Hall, with an estimated IRT ability measure of 3.44 is the highest scoring student to have missed a question, #21. Murta, with an estimated IRT ability measure of 0.58, is the next to the lowest scoring student, missing #11, and seven more. This ranking of unexpected responses is directly related to student test scores. This makes good sense.
Top students are not expected to make wrong marks. No student is expected to miss easy questions. These are basic expectations for IRT.