A Limited Presence of Ideally Difficult Questions in Published Banks of Multiple-choice Questions

摘要

The difficulty of a multiple-choice question is perhaps its most elemental property. For the purpose of discriminating among examinees the ideal difficulty of a multiple-choice question is that the proportion of examinees answering the question correctly (often denoted p) equals 0.50. The optimal item difficulty corrected for examinees guessing among five options (the number for all questions analyzed here) is 0.60. The purpose of this research is to examine samples of questions from published banks of questions to determine the presence of questions that approximate those ideal levels of difficulty.