Two studies of
Accelerated Reader meet the What Works Clearinghouse (WWC) evidence standards. One of the studies evaluated 572 students from grades K to 3 attending 11 schools in a southern school district in the United States. The second study included 32 students in grade 3 attending one school in the Pacific Northwest.
Based on these two studies, the WWC considers the extent of evidence for Accelerated Reader to be medium to large for comprehension and small for reading fluency and general reading achievement. No studies that meet WWC evidence standards with or without reservations examined the effectiveness of Accelerated Reader in the alphabetics domain.