Central in this study is the role of student variables and the fit between secondary education and university education in the explanation of first-year student achievement. The fit between two levels of education can be defined in different ways. In this study the focus is on four fit-aspects: appropriateness of expectations, and the degree to which there is a continuance with respect to teaching approaches, knowledge and workload. The conceptual model, a synthesis of the Model of Student Attrition, the Educational Productivity Model and the Transition Model, is tested with structural equation modelling, based on maximum likelihood estimation. The results indicate that the fit between secondary and university education, in terms of resemblance between the learning environments and experience of some adjustment, as well as social integration, student employment and motivation, affect first-year achievement indirectly through time investment. The theoretical and practical implications of these results are discussed. (Contains 4 tables and 2 figures.)