Balance between control and treatment groups after dropping imbalanced classes Notes: This figure shows the relation of shrinking the estimation sample by excluding classes with highly imbalanced shares of fathers with completed academic high school and the imbalance in fathers’ education between the treatment and control groups. The x-axis shows the number of classes that are dropped. Because of the trimming mechanism, we always drop two classes simultaneously. These are the current classes with the lowest share of fathers who completed academic high school in the treatment group and the current class with the highest share of fathers who completed academic high school in the control group. We consider classes with at least six students. The y-axis shows the point estimate when regressing the treatment indicator PATHS on the baseline characteristic father completed at least a Gymnasium degree. The blue diamond shows the specification in which the imbalance is closest to zero. All models include strata fixed effects for the level of randomization. Robust standard errors are clustered at the school level.