Lewis, D.; O'Brien, M.; Rogan, S.; and Shorten, B., Do Students Benefit From Supplemental Education? Evidence From a First-Year Statistics Subject in Economics and Business, Department of Economics, University of Wollongong, 2005.
Peer assisted study sessions (PASS) are a type of supplemental instruction (SI) that provide students with out-of-class study review sessions with a group of peers. A student, who has successfully completed the subject and acts as a mentor, facilitates the voluntary sessions. Results of the PASS program at the University of Wollongong have been quite positive in that students, on average, who attend more PASS, achieve higher marks. However, a simple comparison does not control for self-selection bias. We control for self-selection in two ways. Firstly, we use Heckman’s two-stage correction technique to analyze the 2002 cohort. Secondly, students in the 2003 cohort were randomly allocated into three groups of equal size: a. A control group that was allocated to normal tutorials with standard class sizes and ineligible to attend PASS b. A group that was eligible to attend PASS and had normal tutorials of standard sizes c. A group that was ineligible to attend PASS but allocated to normal tutorials with smaller class sizes. The results of both methods are consistent and indicate the PASS program has a positive impact on the academic performance of students after correcting for selection bias.