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The WWC review of interventions for Elementary School Math addresses student outcomes in mathematics achievement. The findings below present the authors’ estimates and WWC-calculated estimates of the size and the statistical significance of the effects of Saxon Elementary School Math on students.7 Of the three studies reviewed, one reported statistically significant positive effects. The remaining two studies showed indeterminate effects.
Agodini et al. (2009) reported statistically significant greater achievement on the Early Childhood Longitudinal Study–Kindergarten (ECLS-K) mathematics assessment for schools using the Saxon Elementary School Math program compared to schools using two of the other three comparison curricula. The WWC confirmed those results and also found that impacts for Saxon Elementary School Math were significantly greater than the three comparison curricula considered jointly.
Good, Bickel, and Howley (2006) did not report statistical significance findings for intent-to-treat impacts. Using supplemental results supplied by the authors, the WWC calculations found no statistically significant effect of Saxon Elementary School Math on the performance of kindergarten through third-grade students on the mathematics subtest of the Stanford Achievement Test, Ninth Edition (SAT 9). The effect size of 0.07 on the SAT 9 does not meet the WWC criteria for substantively important effects (an effect size of 0.25 or greater).
Resendez and Manley (2005) reported no significant effects of the Saxon Elementary School Math program on overall math achievement in grades 1–5, as measured by Georgia’s CRCT. Using school-level data provided by the authors, the WWC confirmed that Saxon Elementary School Math did not have a statistically significant effect on math achievement at each grade level from first to fifth grade. Due to the lack of student-level data, the effect size and improvement index could not be calculated.
The WWC rates the effects of an intervention in a given outcome domain as positive, potentially positive, mixed, no discernible effects, potentially negative, or negative. The rating of effectiveness takes into account four factors: the quality of the research design, the statistical significance of the findings, the size of the difference between participants in the intervention and the comparison conditions, and the consistency in findings across studies (see the WWC Procedures and Standards Handbook, Appendix E).