This post explores interpretations of effect sizes in the context of writing proposals for competitive grants in PK-12 education. It translates effect sizes into time-indexed measures of academic growth in Grades PK-11 for instruction in Reading. Such conversion helps to transform the unfamiliar into the familiar.
Time Indexed Effect Sizes and Academic Growth
Research has generated time-indexed effect sizes based on national norms of academic growth in Reading and Mathematics (Lee et al., 2012). It’s possible now to convert Cohen’s d (standardized group mean differences) to d’ (school years of schooling).
Reading (Grades K-5)
In the context of the United States of America, a school year is commonly 180 instructional days (±5 days). Based on the results of research on time-indexed effect sizes—and assuming, for simplicity of calculation, a school year of 180 days—the list summarizes the results of research on time-indexed effect sizes in Reading in Grades K-5:
- In K, an effect size (d) of 0.2 equates to 0.1 of a school year (18 school days), and an effect size (d) of 0.5 equates to 0.3 of a school year (54 school days).
- In Grade 1, an effect size (d) of 0.2 equates to 0.1 of a school year (18 school days), and an effect size (d) of 0.5 equates to 0.3 of a school year (54 school days).
- In Grade 2, an effect size (d) of 0.2 equates to 0.2 of a school year (36 school days), and an effect size (d) of 0.5 equates to 0.4 of a school year (72 school days).
- In Grade 3, an effect size (d) of 0.2 equates to 0.2 of a school year (36 school days), and an effect size (d) of 0.5 equates to 0.6 of a school year (108 school days).
- In Grade 4, an effect size (d) of 0.2 equates to 0.4 of a school year (72 school days), and an effect size (d) of 0.5 equates to 0.9 of a school year (162 school days).
- In Grade 5, an effect size (d) of 0.2 equates to 0.4 of a school year (72 school days), and an effect size (d) of 0.5 equates to 1.0 of a school year (180 school days).
Examples
A meta-analysis of parental involvement in urban elementary schools (Jeynes, 2005) found overall effect sizes of 0.37 for general parental involvement on elementary students’ performance on standardized tests. For those standardized tests that measured performance in Reading, this equates to: 36 school days (in Grades K-1), to 54 school days (Grade 2), to 60 school days (Grade 3), to 118 school days (Grade 4), and to 126 school days (Grade 5).
The same meta-analysis of parental involvement in urban elementary schools (Jeynes, 2005) found overall effect sizes of 0.40 for programs of parental involvement on elementary students’ performance on standardized tests. For those standardized tests that measured performance in Reading, this equates to: 42 school days (in Grades K-1), to 60 school days (Grade 2), to 84 school days (Grade 3), to 132 school days (Grade 4), and to 144 school days (Grade 5).
Reading (Grades 6-12)
Based on the results of the same research on time-indexed effect sizes, the list below summarizes the noteworthy results of research on time-indexed effect sizes in Reading in Grades 6-12:
- In Grade 6, an effect size (d) of 0.2 equates to 0.6 of a school year (108 school days), and an effect size (d) of 0.5 equates to 1.4 of a school year (252 school days).
- In Grade 7, an effect size (d) of 0.2 equates to 0.8 of a school year (144 school days), and an effect size (d) of 0.5 equates to 1.9school years (342 school days).
- In Grade 8, an effect size (d) of 0.2 equates to 0.5 of a school year (180 school days), and an effect size (d) of 0.5 equates to 2.5 school years (450 school days).
- In Grade 9, an effect size (d) of 0.2 equates to 0.8 of a school year (144 school days), and an effect size (d) of 0.5 equates to 1.9 school years (342 school days).
- In Grade 10, an effect size (d) of 0.2 equates to 0.5 of a school year (90 school days), and an effect size (d) of 0.5 equates to 1.3 school years (214school days).
- In Grade 11, an effect size (d) of 0.2 equates to 0.5 of a school year (90 school days), and an effect size (d) of 0.5 equates to 1.3 school years (214 school days).
Examples
A meta-analysis of parental involvement in urban secondary schools (Jeynes, 2007) found overall effect sizes of 0.47 for general parental involvement on secondary students’ performance on standardized tests. For those standardized tests that measured performance in Reading, this equates to: 238 school days (Grade 6), to 320 school days (Grade 7), to 420 school days (Grade 8), to 320 school days (Grade 9), to 200 school days (Grade 10), and to 200 school days (Grade 11).
The same meta-analysis of parental involvement in urban secondary schools (Jeynes, 2007) found overall effect sizes of 0.36 for programs of parental involvement on secondary students’ performance on standardized tests. For those standardized tests that measured performance in Reading, this equates to: 185 school days (Grade 6), to 234 school days (Grade 7), to 315 school days (Grade 8), to 234 school days (Grade 9), to 152 school days (Grade 10), and to 152 school days (Grade 11).
Observations
Conversion of effect sizes into instructional day equivalents is one way that seekers of competitive grants can translate abstruse research findings into more concrete and familiar terms.
The meta-analyses cited here are by no means the only ones available to eligible applicants for competitive grants in PK-12 Education. They are purely illustrative of what’s available. Grant seekers may use such findings in Research Rationales or Reviews of Literature – and elsewhere in proposals – to persuade reviewers that a project is likely to yield results of practical significance (e.g., improved academic achievement through parental involvement), and thus worthy of an investment of a funder’s scarce resources.
Note
The conversions of effect sizes into instructional days, as represented in this post and its graphics, derive from: Jaekyung Lee, Jeremy Finn, and Xiaoyan Liu, “Time-indexed Effect Size for P-12 Reading and Math Program Evaluation.” Paper presented at the Society for Research on Educational Effectiveness (SREE) Spring 2012 Conference, Washington, DC on March 9, 2012. It is available here.