Reporting effect sizes as a supplement to statistical significance testing in reading instruction studies

The far-reaching effects of literacy achievement have heightened the interest of educators and non-educators alike in the teaching of reading. Successful efforts to improve reading achievement emphasise identification and implementation of evidence-based practices that promote high rates of achievement. Behind the concept of evidence-based instruction lies the notion of scientifically valid and replicable research that can help educators make effective choices. The purpose of the article is to review the statistical significance reporting practices in reading instruction studies and to provide guidelines for when to calculate and report effect sizes in educational research. A review of six readily accessible (online) and accredited journals publishing research on reading instruction indicated that researchers / authors rely very heavily on statistical significance testing and very seldom, if ever, report effect size measures when documenting their results.