| Exhibit 15. Relative Gap Reduction (RGR): All Interventions Combined One Year After the Intervention Year |
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|---|---|---|---|---|---|---|---|---|---|---|
| Average at follow-up | Gap at follow-up (Std. Units) | |||||||||
| Grade 3 Cohort | Average at Baseline | Gap at baseline (Std. Units) |
Intervention Group |
Control Group | Intervention Group |
Control Group | Impact | RGR | ||
| Word Attack | 92.4 | 0.50 | 97.4 | 92.1 | 0.17 | 0.53 | 5.3 | * | 0.68 | |
| TOWRE PDE | 85.5 | 0.97 | 90.5 | 86.6 | 0.63 | 0.90 | 4.0 | * | 0.29 | |
| Word Identification | 88.7 | 0.76 | 90.9 | 88.6 | 0.61 | 0.76 | 2.3 | * | 0.20 | |
| TOWRE SWE | 86.6 | 0.90 | 91.7 | 90.0 | 0.55 | 0.67 | 1.7 | * | 0.17 | |
| AIMSweb | NA | NA | NA | NA | NA | NA | NA | NA | ||
| Passage Comprehension | 91.6 | 0.6 | 93.4 | 91.3 | 0.44 | 0.58 | 2.1 | * | 0.24 | |
| GRADE | 86.1 | 0.9 | 79.6 | 78.6 | 1.36 | 1.42 | 1.0 | 0.05 | ||
| Average at follow-up | Gap at follow-up (Std. Units) |
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| Grade 5 Cohort | Average at Baseline | Gap at baseline (Std. Units) |
Intervention Group |
Control Group | Intervention Group |
Control Group | Impact | RGR | ||
| Word Attack | 93.2 | 0.5 | 97.3 | 94.7 | 0.18 | 0.36 | 2.7 | * | 0.5 | |
| TOWRE PDE | 81.0 | 1.3 | 88.0 | 86.3 | 0.8 | 0.91 | 1.7 | 0.13 | ||
| Word Identification | 88.7 | 0.75 | 91.1 | 91.7 | 0.6 | 0.56 | -0.6 | -0.07 | ||
| TOWRE SWE | 84.2 | 1.05 | 88.6 | 87.2 | 0.76 | 0.85 | 1.4 | 0.11 | ||
| AIMSweb | NA | NA | NA | NA | NA | NA | NA | NA | ||
| Passage Comprehension | 92.6 | 0.49 | 91.0 | 92.2 | 0.6 | 0.5 | -1.1 | -0.15 | ||
| GRADE | 91.2 | 0.59 | 88.4 | 87.7 | 0.8 | 0.8 | 0.7 | 0.06 | ||
| NOTE: RGR is defined as RGR=(Impact/100-Average for Control Group at follow-up). | ||||||||||
| NOTE: Gap is defined as (100-Average Score)/15, where 100 is the population average and 15 is the population standard deviation. | ||||||||||
| NOTE: Values for AIMSweb are not available because normed standard scores are unavailable. | ||||||||||
| NOTE: According to the first row of estimates, students in the third-grade cohort achieved an average standardized score of 92.4 on the Word Attack test at “baseline,” that is, shortly after the beginning of third grade—the intervention year. One year after the intervention year, that is, at “follow-up,” the students participating in any intervention achieved an average standardized score of 97.4, and the students in the control group achieved an average standardized score of 92.1, implying a statistically significant impact of 5.3 points. The “gap at baseline,” measured as the difference between the population average (100) and the study sample average (92.4) divided by the population standard deviation (15), was 0.5. One year after the intervention year, the gap was reduced 68 percent (see the “RGR”), when the reduction is measured as the impact (5.3) divided by the difference between the population average (100) and the control group average (92.1). The calculations described in this note might produce results that are slightly different from the estimates in the table due to rounding. | ||||||||||
| * Impact is statistically significant at the 0.05 level. | ||||||||||