In this article, the authors successively present two case studies based on an original use of administrative data banks produced by the Québec and British Columbia Departments of Education. The studies differ both in terms of the indicator used (school performance in exams versus the high school graduation rate), and the definition of the target group (allophone students versus black students). However, a comparison of their results reveals largely converging trends on school success and factors that influence it in relation to the importance of inter-group differences. In this respect, the students’ origins and their mastery of the language is more significant than their socio-economic group. Certain factors have a different effect than for the overall population. The boys’ deficit and arriving at secondary school late are, in fact, less important.