Rank comparisons amongst teenagers and suicidal ideation.

We study how competition amongst known peers at the highest-stakes exam in Korea impacts students' mental health and induces them to express suicidal ideation. Using panel data on Korean students from 2003 to 2007, we exploit a randomization of students' peers (upon entering middle school) to uncover a relationship between students' rank at the CSAT (highest-stakes exam in Korea) and their mental health, more particularly their suicidal thoughts. We find that (i) students' rank amongst peers from middle school affects their suicidal ideation: the farther down in the classification, the more prone to have suicidal thoughts they are; (ii) this association is not capturing the impact of the national ranking at CSAT, which is controlled for in all our specifications; (iii) when reestimating separately our regressions for male and female students, we find all of this association is driven by female students. Male students are more prone to experience other negative feelings such as anxiety or loneliness, but these only appear one year later. Our results confirm that social comparisons with peers matter a lot for individual well-being and mental health. They contribute to building a case against extreme levels of competition at younger ages, as teenagers -especially young girls- suffer deeply from comparing themselves to their peers.