This paper re-examines the wage returns to the 1972 Raising of the School Leaving Age (RoSLA) in England and Wales using a high-quality administrative panel dataset covering the relevant cohorts for almost 40 years of their labour market careers. With best practice regression discontinuity methods we find at best a zero return to the additional education for men. However, we contend that regression discontinuity methods in this context will give unreliable estimates of the return. Using the panel data to correct for this we find a local average treatment effect of 7% over the lifetime for this additional year of education.