Objective Structured Practical Examination and Conventional Practical Examination: a Comparison of Scores

Over the last few decades in India, a gradual transition has occurred from conventional practical examination (CPE) to objective methods of evaluation in the form of objective structured practical examination (OSPE). Opinions differ on the relative reliability of the two methods. The objective of this study was to verify the reliability of subjective assessment of practical laboratory skills vis-a-vis objective practical assessment. This retrospective study was based on the analysis of the results of end-semester practical examinations given to the entire cohort of 50 students in the Department of Physiology in our institute in the academic year 2012–2013. All students were assessed by both methods, CPE and OSPE, in their second end-semester practical examination. The difference of scores in OSPE and CPE was calculated. The OSPE and CPE scores were then sorted in descending order of their differences. Regression analysis was performed to evaluate the association of the two scores. Bland-Altman analysis of differences and averages between OSPE and CPE score was also done. The average scores obtained by the students in the two methods were nearly equal, i.e., 61.2 in OSPE and 61.5 in CPE. However, there were some students who scored more in OSPE and some who scored more in CPE: There was no consistent pattern in these differences. It can be inferred from this study that the law of averages conceals the stark subjectivity inherent in viva voce; it corrupts the reliability of the marks obtained by the student in practical assessment. This can be overcome by the use of OSPE.