In 2010 the Faculty of Science at the University of Wollongong (UOW) decided to inform its admissions policy by analysing the results in the introductory chemistry subject CHEM101. The data was analysed by members of the School of Mathematics and Applied Statistics using a generalised linear model. This paper discusses the model and its implications. One of the conclusions is that the level of mathematics studied for the Higher School Certificate (HSC) is a better predictor of performance in CHEM101 than either the HSC Chemistry mark or the student's Australian Tertiary Admission Rank. As a result of the analysis in this article, the Faculty of Science at UOW changed its early admission procedures. A pdf file of a presentation by the first author on this material and an interactive passing probability calculator based on the model are available at  and  respectively.