“Statistical,” “Practical,” and “Clinical”: How Many Kinds of Significance Do Counselors Need to Consider?

The present article reviews and distinguishes 3 related but different types of significance: “statistical,” “practical,” and “clinical.” A framework for conceptualizing the many “practical” effect size indices is described. Several effect size indices that counseling researchers can use, or that counselors reading the literature may encounter, are summarized. A way of estimating “corrected” intervention effects is proposed. It is suggested that readers should expect authors to report indices of “practical” or “clinical” significance, or both, within their research reports; and it is noted that indeed some journals now require such reports.