It is difficult to ensure that incoming students enrol in first year courses at a level that is commensurate with their ability. Not only do students come from a diverse range of backgrounds, but mathematics at university is, in general, more rigorous and conceptual than it is at high school, and success at high school does not always guarantee success at university. This paper reports on a test that was designed to help students decide whether or not to enrol in the highest level first year mathematics course (MATH1901) at the University of Sydney. Students' performance on the test is analysed to determine whether or not the test can be used to predict success in MATH1901.