The Role of Item Analysis in Detecting and Improving Faulty Physics Objective Test Items

Abstract

Results of candidates’ level of achievement in physics tests being conducted by public examining bodies show that candidates are not doing well in these public examinations. One of the reasons for the low level achievement in physics may be due to faulty test items that are being administered to candidates each year. The use of faulty items may be as a result of not conducting thorough analysis of these items before they are administered to candidates. In this study, therefore, the author examined the role of item analysis in detecting faulty items and in improving the quality of physics objective test items.

Physics Paper 2 (PP2) of 2012 West Africa Examination Council consisting of 50 multiple choice items was administered to 900 senior secondary school three students (Age 16-18 years), who were randomly selected from 16 senior secondary schools in Ibadan Educational Zone I, Oyo State, and Irewole Local Government Area, Osun State, Nigeria. Specifically the difficulty and discriminating indices of each of the 50 items in PP2 were determined. Analyses of the students’ responses to the 50-item PP2 were carried out using both Classical Test Theory and Item Response Theory. Results of the analysis showed that some of the items were faulty in that their difficulty indices were very high and some items could not discriminate between high achievers and low achievers.

These results imply that public examining bodies should carry out thorough analysis of their test items before they are administered to their candidates. More importantly the results of the analysis should be communicated to physics teacher so that they can use the information to clarify some concepts that may be confusing to students in physics.

Keywords: Difficulty index, Discriminating index, Item response theory, Classical test theory, Physics objective test.