Empirical evidence mostly describes the negative effects of grade repetition on academic performance. Nevertheless, the international use of this educational policy is still widespread. In this study, drawing on data for the Spanish case, we provide additional evidence on the need to consider different policies to grade repetition in order to enhance the achievement of low-performers. These alternative policies should be based on two main principles: individualized treatment and early intervention. Results have been achieved from the application of a novel methodology which allows to combine microdata from two international educational assessments.