Self-selection in school choice

We study self-selection in centralized school choice, a strategy that takes place when students submit preferences before knowing their priorities at schools. A student self-selects if she decides not to apply to some schools despite being desirable. We give a theoretical explanation for this behavior: if a student believes her chances of being assigned to some schools are zero, she may not rank them even when the mechanism is strategyproof. Using data from the Mexico City high school match, we find evidence that self-selection exists and exposes students especially from low socio-economic backgrounds to strategic mistakes. Correcting these mistakes leads to an increase in participation of students from low socio-economic backgrounds. These findings question the effectiveness of equal access provided by school choice, and we argue it can be improved by changing the timing of submission.