Effect-size reporting practices in AJSLP and other ASHA journals, 1999-2003.

A census of effect-size practices in the past 5 volumes of American Speech-Language-Hearing Association journals was accomplished. Inclusion of effect size in quantitative research reports increased from 5 reports with effect size in 1990 to 1994 to 120 reports in 1999 to 2003. Nonetheless, effect size was reported less than 30% of the time when inferential statistics were used, and only half of those reports included an interpretation of effect size. This article presents case exemplars to illustrate the use and value of effect size and includes suggestions for interpreting effect size. Researchers are encouraged to routinely report effect size and to interpret effect size in a way that facilitates the application of research to practice.