Comparing IRT difficulty and NCLEX-RN 10,000 question difficulty ratings

In order to determine the relationship between question difficulty level in the NCLEX-RN 10,000 and IRT analysis difficulty we calculated correlations between the IRT-determined difficulties and the question difficulties previously determined by the NCLEX-RN 10,000. This analysis used the top 100 NCLEX-10,000 items and 2,000 students’ worth of data.