"Cooperative Integrated Reading and Composition"[R] is a reading and writing program for students in grades 2 through 6. It has three principal elements: story-related activities, direct instruction in reading comprehension, and integrated language arts/writing. Daily lessons provide students with an opportunity to practice comprehension and reading skills in pairs and small groups. Pairs of students read to each other; predict how stories will end; summarize stories; write responses to questions posed by the teacher; and practice spelling, decoding, and vocabulary. Within cooperative teams of four, students work to understand the main idea of a story and work through the writing activities linked to the story. A Spanish version of the program is available for grades 2 through 5. The What Works Clearinghouse (WWC) reviewed 52 studies of "Cooperative Integrated Reading and Composition"[R] for adolescent learners. Two studies meet WWC evidence standards with reservations; the remaining 50 studies do not meet either WWC evidence standards or eligibility screens. Based on these studies, the WWC found potentially positive effects on comprehension and general literacy achievement for adolescent learners. The conclusions presented in this report may change as new research emerges. Appendices include: (1) Study characteristics; (2) Outcome measures; (3) Summary of study findings included in the ratings; (4) Summary of one-year implementation findings; (5) "Cooperative Integrated Reading and Composition"[R] ratings; and (6) Extent of evidence by domain. (Contains 10 footnotes.)