To write effective items, it is necessary to examine whether they are measuring the fact, idea, or concept for which they were intended. This is done by studying the student’s responses to each item. When formalized, the procedure is called “item analysis”. It is a scientific way of improving the quality of tests and test items in an item bank.
An item analysis provides three kinds of important information about the quality of test items.
- Item difficulty: A measure of whether an item was too easy or too hard.
- Item discrimination: A measure of whether an item discriminated between students who knew the material well and students who did not.
- Effectiveness of alternatives: Determination of whether distractors (incorrect but plausible answers) tend to be marked by the less able students and not by the more able students.
Item difficulty, item discrimination and the effectiveness of distractors on a multiple-choice test are automatically available with ParScore’s item analysis. An illustration of ParScore’s “Standard Item Analysis Report” printout is attached.
Additional Item Analysis Links
- Optimal Item Difficulty
- Item Discrimination I
- Item Discrimination II
- Distractors and their Effectiveness
- Reliability of a Test
- Validity of a Test
See the sample Item Analysis report here.