Found Effects

The WWC found accelerated middle schools to have potentially positive effects on staying in school and positive effects on progressing in school

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 as well as 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 and that 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 the three studies of accelerated middle schools that met evidence standards, the average improvement index for staying in school is +18 percentile points, with a range of –5 to +33 percentile points across the studies. Based on these three studies, the average improvement index for progressing in school is +35 percentile points, with a range of +15 to +44 percentile points across the studies.

Summary

The WWC reviewed three studies on accelerated middle schools. One study met WWC evidence standards, and two studies met WWC evidence standards with reservations. Based on these three studies, the WWC found potentially positive effects on staying in school and positive effects on progressing in school. The conclusions in this report may change as new research emerges.