Item analysis is used to evaluate test items and identify areas for improvement. It examines the difficulty level, discriminating power, and effectiveness of distractors for multiple choice items. Item difficulty is measured by the percentage answering correctly, and discrimination is measured by comparing the percentage of high-scoring vs low-scoring students answering correctly. Item analysis data can be used to identify weaknesses in student learning, determine if items should be retained, revised, or replaced, and improve the quality of future tests.