Wisconsin's influential Learnfare initiative is a conditional cash "penalty" program that sanctions a family's welfare grant when covered teens fail to meet school attendance targets. In the presence of reference-dependent preferences, Learnfare provides uniquely powerful financial incentives for student performance. However, a 10-county random-assignment evaluation suggested that Learnfare had no sustained effects on school enrollment and attendance. This study evaluates the data from this randomized field experiment. In Milwaukee County, the Learnfare procedures were poorly implemented and the random-assignment process failed to produce balanced baseline traits. However, in the nine remaining counties, Learnfare increased school enrollment by 3.5 percent (effect size=0.08) and attendance by 4.5 percent (effect size=0.10). These results suggest that well-designed financial incentives may be an effective mechanism for improving the school persistence of at-risk students at scale. (Contains 9 tables.)