Found effects

The WWC found Reading Recovery® to have positive effects in the alphabetics and general reading domains and potentially positive effects in the fluency and comprehension domains

Improvement index

The WWC computes an improvement index for each individual finding. In addition, within each outcome domain, the WWC computes an average improvement index for each study and an average improvement index across studies (see Technical Details of WWC-Conducted Computations). The improvement index represents the difference between the percentile rank of the average student in the intervention condition versus the percentile rank of the average student in the comparison condition. Unlike the rating of effectiveness, the improvement index is entirely based on the size of the effect, regardless of the statistical significance of the effect, the study design, or the analyses. The improvement index can take on values between -50 and +50, with positive numbers denoting results favorable to the intervention group.

The average improvement index for alphabetics is +34 percentile points across three studies, with a range of –10 to +50 percentile points. For fluency, the average improvement index is +46 percentile points, with a range of +32 to +49 percentile points across outcomes in one study. For comprehension, the average improvement index is +14 percentile points across two studies, with a range of +6 to +21 percentile points. For the general reading domain, the average improvement index was +32 percentile points across five studies, with a range of –5 to +50 percentile points.

Summary

The WWC reviewed 78 studies that investigated the effects of Reading Recovery®. Four studies met WWC evidence standards and one met WWC evidence standards with reservations. Based on these five studies, the WWC found Reading Recovery® to have positive effects in the alphabetics and general reading achievement domains. Reading Recovery® was found to have potentially positive effects in the fluency and comprehension domains. The evidence presented in this report may change as new research emerges.