Success in tertiary studies is often measured using quality indicators (e.g. grade point average) and completion rates. These measures are particularly difficult to use in many non-degree programmes where completion can be very low (often due to high levels of mobility across institutions and in and out of the workforce). This study uses student achievement and demographic data from a large New Zealand polytechnic to provide an alternative method for determining success, which then allows comparisons across programmes and institutions regardless of differences in grading scales and completion rates. Furthermore, by instituting this new method it is possible to identify more precisely the groups of students who are at the greatest risk of failure while identifying programmes that require further investigation regarding low achievement and/or low completion rates. It is suggested that this model is widely applicable across different educational systems. Implications for educational policy makers are discussed.