Early childhood health shocks, classroom environment, and social-emotional outcomes.

This study finds that experiencing early childhood health shocks before primary school exerts negative externalities in the middle school classroom. Students randomly assigned to classrooms in which more classmates experienced early childhood health shocks are more likely to have worse social-emotional outcomes, including emotional distress, less engagement with school activities, and poor social acclimation with classmates. These effects operate by damaging inter-student relationships, and are unlikely to operate by affecting teachers' behaviors or preferences. Parents may mitigate negative peer effects by encouraging children to talk about their concerns or interactions at school. The effects on test scores are not statistically significant.