This study examined whether attending a Knowledge is Power Program (KIPP) middle school improved students' reading, math, social studies, and science achievement for up to 4 years following enrollment. The study reported that students attending KIPP middle schools scored statistically significantly higher than matched students on all of the state assessments and follow-up periods examined, including reading and math 1-4 years following enrollment (effect sizes ranging from 0.05 to 0.36), and social studies and science 3-4 years following enrollment (effect sizes of 0.25 and 0.33, respectively). The portion of the study that used a quasi-experimental design meets What Works Clearinghouse (WWC) evidence standards with reservations. The study established that KIPP and non-KIPP students were similar on measured characteristics such as baseline test scores and demographics, and controlled for baseline characteristics of students in the analysis. [The following study is reviewed in this "Quick Review": Tuttle, C. C., Gill, B., Gleason, P., Knechtel, V., Nichols-Barrer, I., & Resch, A. (2013). "KIPP middle schools: Impacts on achievement and other outcomes, final report." Washington, DC: Mathematica Policy Research (ED540912).]