Abstract: Given the fact of the fierce academic competition and gaming in China, we ask the question of whether the academic return of private tutoring comes at the expense of mental health. This topic involves the investigation and analysis of the dual effects of private tutoring. In this paper, an analytical framework is constructed through mathematical derivation and theoretical deduction, and a multi-layer linear model is applied to explore the influence of individual time input and the level of participation in private tutoring on students' academic performance and mental health. We further explore the trend of the dual effect of private tutoring when there are changes in the level of participation in after-school tutoring of the class. By using the China Education Panel Survey (CEPS) data in the years of 2014 and 2015, this study reaches a solid and consistent finding that although investing time in private tutoring can boost academic achievement, it has a significant negative impact on students' mental health. With the increase of average tutoring and participation level in the class, the positive effect of the time invested in after-school tutoring on academic performance continues to weaken while the negative impact on mental health is gradually enhanced. The main triggers for increasing mental health impact are the weakening of the social comparison effect as well as the enhancement of the role stress effect and the sleep deprivation effect. In conclusion, this study reveals a trend that in the context of intense academic competition and challenges, over the time the academic reward of private tutoring reduces while the mental health cost rises. This conclusion has important theoretical significance in promoting further research on the micro-gaming mechanism and heterogeneity models of private tutoring. At the same time, it also provides some insights for other countries on policies of how to understand and respond to the phenomenon of private tutoring.

Key words: private tutoring, peer competition and game, academic achievement, mental health