Controlling response shift bias: the use of the retrospective pre-test design in the evaluation of a master's programme
Abstract
Traditionally the measures used to evaluate the impact of an educational programme on student outcomes and the extent to which students change is a comparison of the student's pre-test scores with his/her post-test scores. However, this method of evaluating change may be problematic due to the confounding factor of response shift bias when student self-reports of change are used. Response shift bias occurs when the student's internal frame of reference of the construct being measured, for example research ability or critical thinking, changes between the pre-test and the post-test due to the influence of the educational programme. To control for response shift bias the retrospective pre-test method was used to evaluate the outcomes achieved from students completing a research module at master's level. The retrospective pre-test method differs from the traditional pre-test-post-test design in that both post-test and pre-test perceptions of respondents are collected at the same time. The findings indicated that response shift bias was evident in that the programme had significantly greater impact on outcomes than identified using the traditional pre-test-post-test design leading to the conclusion that students may overestimate their ability at the commencement of an educational programme. The retrospective pre-test design is not a replacement for the traditional pre-test-post-test measures but may be a useful adjunct in the evaluation of the impact of educational programmes on student outcomes.