What Works Clearinghouse documents Reading Recovery’s scientific research base
 

The What Works Clearinghouse (WWC), an initiative of USDE's Institute of Education Sciences, is a central, trusted source of information for decision makers. Established in 2002, the WWC reviews and assesses research evidence for educational programs, products, practices, and policies.

Research on beginning reading
The WWC publishes intervention reports that assess research on beginning reading curricula and instructional strategies for students from kindergarten through third grade. By fall 2011, the WWC has reviewed studies for 171 programs in the beginning reading category, and only 26 met their rigorous standards. The WWC translates effect sizes from research into in improvement index that reflects the change in a student's percentile rank that can be expected if the student has the intervention. Administrators use these index ratings to make informed decisions while selecting the right program for their schools and districts.

Reading Recovery's evidence
Among all programs reviewed, Reading Recovery received the highest rating in general reading achievement, and positive ratings across all four domains -- alphabetics (phonics and phonemic awareness), fluency, comprehension, and general reading achievement.

The report includes an improvement index to reflect the strength of the Reading Recovery intervention. Scores on this index can range from -50 to +50. The improvement index scores for Reading Recovery students show large and impressive effect sizes.