Planning special purpose high schools and private tutoring needs in Korea: A longitudinal, casual relationship

This study estimated the longitudinal causal effect of special purpose high school (SPHS) aspiration on the participation and expenditure of private tutoring (PO among Korean middle school students using data from the Korean Education Longitudinal Study (KELS). Reviews of previous studies revealed methodological challenges for causal reasoning on this matter as 1) retrospective study is inappropriate for the research question, 2) zero-inflation of data prevents normal-theory based inference and 3) treatment effect for the treated (TET) is a more appropriate analytic strategy. Considering these challenges, this study constructed a propensity based matched sample and adopted a two-part model and multilevel growth analysis for TET estimation. Results show that SPHS aspiration group's PT participation rate were high and stable at about 84% throughout the middle school period and will not decrease even if they changed their minds to go to general high schools (GHS). PT expenditure increases over time under both SPHS and GHS conditions, however, the rate of change was much higher under the SPHS condition.