After collecting students' self-ratings on various study related tasks from 291 first year students enrolled in Biology in 1993, a theoretical model of the way in which (a) general student background factors such as sex, age and language at home and (b) particular factors concerned with students' learning and writing difficulties operate to influence end-of-year Biology results was developed. The proposed model was then tested using Partial Least Squares Path Analysis (PLSPATH) to examine the degree to which the theoretical model was an appropriate representation of the data. Results showed that university entrance score, gender, first year difficulties and learning and writing difficulties had a direct impact on student performance at the end of first year. Unsurprisingly, university entrance score was the strongest predictor of end-of-year performance, but other more interesting relationships emerged as well eg. between self-rating and achieved results for female students. This study provides useful information regarding the way in which different variables operate to influence achievement in higher education in first year as well as for the planning and implementation of the most effective assistance for tertiary students with difficulties in the area of academic learning and writing.