„Achievement-based selection can improve student achievement before selection takes place by raising incentives to study. This effect has to be taken into account when evaluating school systems with different degrees of selectivity. Our results suggest, for example, that even if students do not benefit from attending selective schools, the presence of selective schools alone can enhance skill acquisition if strong preferences for them induces greater study effort.“
Maximilian Bach u. a., Understanding the Response to High-Stakes Incentives in Primary Education (2020), S. 6.