Found effects

The WWC found LiPS^® to have potentially positive effects for alphabetics and no discernible effects for 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 entirely based on the size of the effect, regardless of the statistical significance of the effect, the study design, or the analysis. The improvement index can take on values between –50 and +50, with positive numbers denoting favorable results.

The average improvement index for alphabetics is +17 percentile points in the one study across two comparison groups, with a range of –1 to +35 percentile points across findings.

The average improvement index for comprehension is +6 percentile points in the one study across two comparison groups, with a range of 0 to +20 percentile points across findings.

Summary

The WWC reviewed 37 studies on LiPS^®. One of these studies meets WWC evidence standards; no studies meet WWC evidence standards with reservations; the remaining 36 studies do not meet either WWC evidence standards or eligibility screens. Based on the one study, the WWC found potentially positive effects in alphabetics and no discernible effects in comprehension. The conclusions presented in this report may change as new research emerges.