Using two different approaches, researchers from Mathematica Policy Research conclude that Knowledge Is Power Program (KIPP) students scored higher than comparison students not attending KIPP schools by an amount equivalent to 11 months of additional learning in math and about eight months in reading. The impact was unevenly distributed across KIPP schools, and a number of factors were identified that were weakly related to this variation in effectiveness. The evaluation study was carefully planned and executed, and the results are about the same magnitude as those from other experiments in education. The KIPP outcomes may be substantial if found to persist into later grades. The benefits, however, appear to be overstated in the evaluation study for two reasons. First, translating educational outcomes into “months” of additional learning is an inexact science and can lead to absurd results if taken literally. Second, reported measures of effectiveness that take attrition into account are smaller than the estimates used to draw conclusions about the effectiveness of KIPP. In addition, the effect of KIPP on higher-order reasoning is less certain than is portrayed in the report. The latter topic requires additional empirical work to provide greater clarity.