The classwide peer tutoring program: implementation factors moderating students' achievement.

We conducted a study designed to assess implementation of the classwide peer tutoring program and the relationship between implementation variation and student outcome. A clinical replication design was used. Five volunteer elementary teachers were trained to implement the program; their implementation was monitored for 19 consecutive weeks during 1 school year. Overall, the results indicated that specific variations in program implementation were associated with students' responses to treatment. It was also demonstrated that different teachers' applications of the program produced differential levels of student outcome. Implementation factors related to lower spelling achievement were (a) reduced opportunities to receive program sessions, (b) reduced probabilities of students' participation in program opportunities, (c) too many students assigned unchallenging spelling words, and (d) reduced rates of daily point earning reflecting lower levels of spelling practice during tutoring sessions. The implications of these findings and methods of preventing these implementation problems are discussed in the context of quality assurance and social validity.