A multivariate model to explain student success and failure at the Open University of the United Kingdom is outlined. The model is based on the results of an evaluation study that explored the suitability of this teaching system for young people under 21 years old. Twenty-three characteristics were designated as social and psychological problems, and it was hypothesized that the more problems students had, the less likely they would be to gain a credit. Younger students were assigned scores ranging from zero to 23 depending upon the number of problems they exhibited. It was found that educationally qualified students with low scores were particularly successful and unqualified students with high scores were very unlikely to gain a credit. In order to attach weights to individual problems, a stepwise multiple regression was conducted using the 23 problems as independent variables and whether or not a credit was gained as the dependent variable. The resulting variables was an extremely good predictor for first-year progress among younger students. When performance across the age range was examined, it was found that younger students with few social and psychological problems fared as well as their older counterparts and that the relatively poor progress made by younger students could partly be explained by the fact that their study environments and personality characteristics tended to be less suited to distance study. However, it was also shown that when numerous problems existed it was the older students who were more willing or able to overcome them. It is concluded that environmental and psychological factors are at least as important as academic ability in determining student performance, and that the model can be used to identify high-risk students. A bibliography is appended. (SW)