Found effects

The WWC found CIRC® to have no discernible effects on comprehension

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 based entirely 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 comprehension is +4 percentile points in two studies, with a range of +1 to +8 percentile points across findings.

Summary

The WWC reviewed 11 studies on CIRC®. Two studies met WWC standards with reservations; the others did not meet WWC evidence screens. Based on the two studies, the WWC found no discernible effects in the comprehension domain. The evidence presented in this report may change as new research emerges.