Found Effects

The WWC found Doors to Discovery™ to have potentially positive effects on oral language and print knowledge, and no discernible effects on phonological processing and math

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 WWC Procedures and Standards Handbook, Appendix F). 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.

Based on two studies, the average improvement index for Doors to Discovery™ on two measures of oral language is +9 percentile points, with a range of +6 to +12 percentile points across findings, and the average improvement index on five measures of print knowledge is +16 percentile points, with a range of +2 to +37 percentile points. Based on one study, the average improvement index for Doors to Discovery™ on one measure of phonological processing is +7 percentile points, and the average improvement index on three measures of math is 0 percentile points, with a range of –5 to +5 percentile points.

Summary

The WWC reviewed six studies on Doors to Discovery™. One of these studies meets WWC evidence standards, one study meets WWC evidence standards with reservations, and the remaining four studies do not meet either WWC evidence standards or eligibility screens. Based on the two studies, the WWC found potentially positive effects on oral language and print knowledge, and no discernible effects on phonological processing and math. The conclusions presented in this report may change as new research emerges.