Unemployment of the unqualified young workers in Canada has always been a preoccupation and is doomed to increase with the mondialisation of the economy. The first source of non qualification is to dropout of school. In this paper, we consider the effect of working while in school on the probability of dropping out at the secondary level. However, contrary to previous papers we have realised on this subject, we consider here the relation decision to dropout and working while in school in a more complex setting. In this paper, we entertain the possibility of two models to explain the decisions of the individuals in our sample of Statistics Canada's School Leavers Survey. In a first model, school is the0501n preoccupation, while in the second model experience of work while in school is the leading decision. Not knowing a priori, which model a specific individual belongs to, we use a sophisticated econometric model to compute the probability that an individual with given characterictics is part of the first or the second model. The research identifies several determinants of dropping out and different policies which can be put in action by the government in order to reduce dropout.