Effect Sizes as Evidence – The single most important pitfall to avoid

Despite widespread use of effect sizes across industries as a standardized measure of impact, effect size calculations remain one of the most incorrectly applied and misinterpreted statistics. An effect size is nothing more than a standardized comparison, or “effect” , that captures the difference between an average value and a meaningful comparison in the metric of standard deviation.

The single most important pitfall for Illinois schools to avoid when interpreting ISBE Student Growth Percentiles (SGPs)

The Illinois State Board of Education (ISBE) recently released student growth percentiles (SGPs) to Illinois school districts in preparation of the new school accountability system and the launch of the new Illinois school report card. While incorporating student growth into the school accountability system is a step in the right direction, it is important to recognize that ISBE SGP results are reported within an accountability context not a school improvement context.