When researchers describe the findings of their studies on the effects of educational interventions, they report on whether there were statistically significant differences between the intervention group and the control group on the outcomes of interest (for example, academic achievement). Statistical significance, however, is not generally understood by those who have not been trained in conducting research. In addition, as the report’s lead author Mark Lipsey of Vanderbilt University explains, “Practical and statistical significance are not the same thing,” and statistical significance provides “little insight into the practical magnitude of the effect. For example, even if the results indicate a statistically significant effect of an intervention, is this effect meaningful in terms of real student learning or achievement, or is there only a trivial impact?”