Does regular online testing enhance student learning in the numerical sciences? Robust evidence from a large data set Simon D. Angus and Judith Watson Simon D. Angus is a lecturer in the Department of Economics, Monash University, Melbourne, Austra- lia; Judith Watson is a lecturer in the School of Economics, University of New South Wales, Sydney, Australia. Address for correspondence: Dr Simon D. Angus, Department of Economics, Monash Univer- sity, Clayton, 3206 VIC, Australia. Email: simon.angus@buseco.monash.edu.au Abstract While a number of studies have been conducted on the impact of online assess- ment and teaching methods on student learning, the field does not seem settled around the promised benefits of such approaches. It is argued that the reason for this state of affairs is that few studies have been able to control for a number of confounding factors in student performance. We report on the introduction of a regular (every 3 weeks) low-mark online assessment tool in a large, first- year business mathematics course at the University of New South Wales, a major Australian university. Using a retrospective regression methodology together with a very large and rich data set, we test the proposition that expo- sure to the online assessment instrument enhances student learning. Signifi- cantly, we are able to control for prior student aptitude, in-course mastery, gender and even effort via a voluntary class attendance proxy. Furthermore, the study incorporates two large, and statistically diverse cohorts as well as manipulations in the model tested to robustly examine the outcomes. Our central result is that higher exposure to the online instrument robustly leads to higher student learning, all else being equal. Various implications for online assessment design, implementation and targeting are also discussed. Introduction Assessment is the most powerful lever teachers have to influence the way students respond to courses and behave as learners. (Gibbs, 1999, p. 41) In recent years, online assessment tools have become increasingly used. Instructors are attracted by savings in both marking time and administrative costs of mark compila- tion, while for students, online quizzes give instantaneous and detailed feedback and greatly enhanced flexibility around the time and place of sitting the test. However, the British Journal of Educational Technology Vol 40 No 2 2009 255–272 doi:10.1111/j.1467-8535.2008.00916.x © 2009The Authors. Journal compilation © 2009 Becta. Published by Blackwell Publishing, 9600 Garsington Road, Oxford OX4 2DQ, UK and 350 Main Street, Malden, MA 02148, USA.