Figure 1 shows our estimates of the average impact of attending a charter school on test scores, expressed
in standard deviation units.
The impacts are presented as effect sizes (which represent the differences between groups
in standard deviation units) for eight measured outcomes across the domains of literacy, language, and math.
[9] If the scores are converted to
standard deviation units (SD), Japan scored 0.9 SD higher than the U.S (all scores in this section refer to eighth grade).
Table 2 Effect Size Contrasts (Cohen's d) in Perceptions of Middle School Students Versus Preservice Teacher Educators Toward STEM Content and Careers (2009 data,
Standard Deviation Units)