This paper examines possible causal relationships of high school dropouts in the lights of 5 major categories: school, educational program, teachers and staff, students, parents and their families. Since the number of high school dropouts – a count variable – is a dependent variable in our model, the Poisson regression model with three-year panel data from 2011 to 2013 is used. Empirical findings are as follows; (1) high school dropouts are more likely to be from small or middle cities than big cities while a school’s size is positively associated with the number of dropouts, (2) after-school programs help students stay in school, (3) incentive for teachers seems to be working positively, (4) academic performance of each student is one of the main determinants for dropping out, and (5) family’s financial stability also plays a significant role in reducing dropouts.