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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 alphabetics is +8 percentile points, with a range of -20 to +15 percentile points; the average improvement index for comprehension is +1 percentile points, with a range of -12 to +19 percentile points.Summary
The WWC reviewed 115 studies on Fast ForWord®. 9Five of these studies met WWC evidence standards, one study met WWC evidence standards with reservations, and the remaining studies did not meet WWC evidence screens. Based on these six studies, the WWC found positive effects on alphabetics and mixed effects on comprehension. The evidence presented in this report may change as new research emerges.
|Institute of Education Sciences