**Abstract**

In the field of medical education, Item analysis is a statistical analysis of student's responses on exam items and the relationship between them. It provides constructive feedback about items quality, increases the effectiveness of the exam, and supports exam validity and reliability. The decision of adding or removing an item should depends mainly on the result of the item analysis. The feedback of item analysis can support modification of instruction methods. This chapter provides a comprehensive review of item analysis (psychometric analysis) and also can be used as methodological guidance to perform an informative analysis. The chapter discusses item analysis under the following headings, importance of item analysis, factors affecting item analysis, parameters of item analysis and application. The parameters of item analysis includes the indices of the internal consistency, difficulty, discrimination, and distractor analysis.

**Keywords:** item analysis, difficulty index, reliability, discrimination index, KR20
