The "Knowledge Is Power Program" ("KIPP") is a nonprofit network of more than 200 public charter schools educating early childhood, elementary, middle, and high school students. The What Works Clearinghouse (WWC) identified four studies of "KIPP" that fall within the scope of the Charter Schools topic area and meet WWC group design standards. One study meets WWC group design standards without reservations, and three studies meet WWC group design standards with reservations. Together, these studies included approximately 21,000 students in middle and high schools across 16 states and the District of Columbia. According to the WWC review, the extent of evidence for "KIPP" on the academic achievement of middle and high school students was medium to large for four outcome domains--mathematics achievement, English language arts achievement, science achievement, and social studies achievement, and was small for one outcome domain--student progression.