Score contribution per author:
α: calibrated so average coauthorship-adjusted count equals average raw count
Grade retention practices are at the forefront of the educational debate. In this article, we measure the effect of grade retention on Spanish students' achievement by using data from Programme for International Student Assessment (PISA). We find that grade retention has a negative impact on educational outcomes, but we confirm the importance of endogenous selection which makes observed differences between repeaters and nonrepeaters appear about 14% lower than they actually are. The effect on scores of repeating is much smaller (--10% of nonrepeaters' average) than the counterfactual reduction that nonrepeaters would suffer had they been retained as repeaters (--24% of their average). Furthermore, those who repeated a grade during primary education suffered more than those who repeated a grade in secondary school, although the effect of repeating at both times is, as expected, larger.