The levels of difficulty and discrimination indices and relationship between them in four-response type multiple choice questions of pharmacology summative tests of Year II M.B.B.S students

Abstract

Background: Item analysis is the process of collecting, summarising and using information from students' responses to assess the quality of test items. Difficulty index (P) and discrimination index (D) are two parameters which help to evaluate the standard of MCQ questions used in an examination, with abnormal values indicating poor quality. Methods: In this study 200 test items of 10 MCQ tests from 2008 to 2012 were selected and analysed to obtain their difficulty and discrimination indices. The relationship between the difficulty index and discrimination index for each test item was determined by Pearson correlation analysis. Results: Mean difficulty index scores of the individual summative tests were in the range of 47.17% to 58.08%. Twenty nine percent of total test items crossed the difficulty index of 70% indicating that those items were easy for the students. Seventy eight percent of the test items showed acceptable (> 0.2) discrimination index. Forty six percent of the test items showed excellent discrimination index. Discrimination index correlated poorly with difficulty index (r=0.11). The correlation is insignificant at 5% (p>0.10). Conclusion: A consistent level of test difficulty and discrimination indices was not maintained from 2008 to 2012 in all the ten summative type A MCQ tests. IeJSME 2013 7(2): 41-46