This paper uses a quasi-experimental, matched comparison group design to estimate the impacts of the Kauffman School on student achievement, attendance, and suspensions. According to our findings, during its first three years of operation, the Kauffman School had positive, statistically significant, and educationally meaningful impacts on student achievement growth in mathematics, reading, and science. The estimated impact of Kauffman School on student attendance is positive and significant in some grades and not significantly different from zero in others. We find that the Kauffman School suspends students at a substantially higher rate than other schools in Kansas City. However, we also see that the number of days suspended for Kauffman students is, on average, small relative to the additional instructional time afforded by the Kauffman School’s extended school day and year. Therefore, it appears that the discipline policy at the Kauffman School can be strictly enforced without resulting in a substantial loss of learning time for suspended students.