"Accelerated Reader"[TM] is a guided reading intervention used to supplement regular reading instruction in K-12 classrooms. Its aim is to improve students' reading skills through reading practice and quizzes on the books students read. The "Accelerated Reader"[TM] program calls for students to select and read a book and then…

This study elaborates the "what works?" question by exploring the effects of variability in program implementation quality on achievement. Particularly, the effects on achievement of computerized assessment of reading were investigated, analyzing data on 51,000 students in Grades 1-12 who read over 3 million books. When minimum implementation…