Found effects

The WWC found Pre-K Mathematics to have positive effects on 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 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 improvement index for math is +22 percentile points across the two studies, with a range of +22 to +23 percentile points across findings.

Findings for comparisons between Pre-K Mathematics and Building Blocks for Math

The analysis for the comparison described below was included in the Clements and Sarama (2006) study, but the findings do not contribute to the overall rating of effectiveness because the WWC included the comparison of Pre-K Mathematics to the business-as-usual comparison group in the rating for the same study, which provides a clearer sense of Pre-K Mathematics' effects. However, the WWC believes that the findings from this comparison provide useful information to practitioners who may be interested in comparing the effects of different curricula. The WWC reports the findings for comparisons of Pre-K Mathematics and Building Blocks for Math here and in Appendix A5.

Math. Clements and Sarama (2006) analyzed group differences between the Pre-K Mathematics combined with DLM Express group and the Building Blocks for Math group for one math outcome measure (Early Mathematics Assessment). The difference between groups was statistically significant and favored children in the Building Blocks for Math group. The improvement index for math is -19 percentile points (Pre-K Mathematics is the intervention group and Building Blocks for Math is the comparison group) for the single finding in the study.

Summary

The WWC reviewed three studies on Pre-K Mathematics. One study met WWC evidence standards and another study met WWC evidence standards with reservations; the remaining study did not meet WWC evidence screens. Based on these two studies, the WWC found positive effects on math. Additional findings that were not considered for the rating of effectiveness indicated that Pre-K Mathematics may not have as large an impact on children's math outcomes as another skills-focused preschool mathematics intervention. The evidence presented in this report may change as new research emerges.