ABSTRACT
Introduction: Difficulty index (P) and discrimination index (D) are the parameters used to evaluate the standard of multiple choice questions (MCQs) in examination. Accordingly the standard of MCQs can be interpreted as excellent, acceptable or poor. This study was intended to find out the standard of MCQs in formative examination in Physiology. The study also intended to find out correlation between P and D. Materials and Methods: There were 240 MCQ items, taken from the past 4 year batches of 100 students and were analyzed for level of difficulty and discrimination index. The relationship between them for each test item was determined by Pearson correlation analysis using SPSS 11.5. Results: There was a wide distribution of item difficulty indices (8.57 to 95.71) and discrimination indices (-0.54 to 0.8).The mean difficulty index (P) was 52.53 + 20.59 and mean discrimination index was 0.30+ 0.18. On average, about 23% of the MCQ items were easy (P >70%), while about 15% were difficult (P <30%). The remaining 62% items were within acceptable range (30 to 70%). In all 4% of the items showed negative discrimination and 21% of the items exhibited poor discrimination. The remaining 75% of the items were in the range of acceptable to excellent discrimination. The discrimination index exhibited slight positive correlation with difficulty index (r = 0.191, P=0.003<0.01). The maximal discrimination (D=0.6-0.8) was observed with moderately easy/difficult items (P = 40% - 60%). Conclusion: The majority (75%) of the items was acceptable as far as difficulty and discriminative indices were concerned. Moderately easy/difficult items had maximal discriminative ability. Too easy and too difficult items gave poor discrimination index. Negative discrimination was observed in only 4% of the items indicating faulty items or incorrect keys.