Given the commonly accepted view that having a mathematically well-educated populace is strategically important, there is considerable international interest in raising attainment, and increasing participation, in post-compulsory mathematics education. In this article, multilevel models are developed with the use of datasets from the UK Department for Education's National Pupil Database (NPD) in order to explore (1) school effects upon student progress in mathematics from age 11-16 in England and (2) student participation in advanced-level mathematics over the following 2 years. These analyses highlight between-school variation in the difference between mathematical and general academic progress. Furthermore, the between-school differences in post-compulsory mathematics participation are large. Importantly, there is no evidence to suggest that schools/departments with higher "contextual value added" from 11-16, a key measure in government accountability processes in England, are also more effective in recruiting and retaining students in post-16 advanced mathematics courses. (Contains 5 tables, 3 figures and 4 notes.)