Impacts of boarding on primary school students’ mental health outcomes – Instrumental-Variable evidence from rural northwestern China

•Using students’ home-to-school distance as an instrumental variable to estimate impacts of boarding on primary school students’ mental health.•Boarding has a significantly negative effect (0.455 SDs) on their mental health status.•The negative effects of boarding on mental health are larger for students with relatively advantageous backgrounds. This paper estimates the impacts of boarding on primary school students’ health outcomes, using data on 7606 students from rural areas of two northwestern provinces (Qinghai and Ningxia) of China. Exogenous variations in students’ home-to-school distance are exploited to address potential endogeneity in their boarding status. Instrumental variable estimates suggest that while boarding has little impact on students’ physical health (measured by height-for-age and BMI-for-age z-scores and hemoglobin concentration levels), it has a significantly detrimental effect on their mental health status, amounting to 0.455 standard deviations (SDs) of the distribution of scores on a Mental Health Test (a modified version of the Children’s Manifest Anxiety Scale). The effect of boarding is more pronounced for students with relatively advantageous backgrounds. For example, boarding boys scored 0.544 SDs higher on the Mental Health Test (suggesting more anxiety problems) than nonboarding boys, and boarders from relatively wealthier families scored 0.754 SDs higher than wealthier nonboarders. ‘