Cram schooling is believed by students and their parents to have positive effects on learning achievement in Taiwan. Using two waves of panel data gathered by the Taiwan Education Panel Study (TEPS) in 2001 and 2003 and the method of propensity score matching (PSM), the present research found that the average treatment effect for participants of mathematics cramming programs is fairly small. Moreover, the PSM analysis revealed that propensity to attend cram school, higher parental education level, and prior mathematics ability are all negatively related to effects of mathematics cramming. (Contains 22 footnotes and 4 tables.)