Reporting and Interpreting Effect Size in Quantitative Agricultural Education Research

TLDR

The Journal of Agricultural Education mandates APA guidelines and the use of accepted research methods, and the APA recommends reporting effect sizes in quantitative studies. This paper aims to explain the rationale for reporting effect sizes in quantitative agricultural education research and to illustrate how to compute them for common analyses. The authors present calculations for effect sizes across typical statistical tests and discuss the underlying assumptions and limitations of such reporting. The study recommends suitable effect size metrics and offers guidance on their interpretation.

Abstract

The Journal of Agricultural Education (JAE) requires authors to follow the guidelines stated in the Publication Manual of the American Psychological Association [APA] (2009) in preparing research manuscripts, and to utilize accepted research and statistical methods in conducting quantitative research studies. The APA recommends the reporting of effect sizes in quantitative research, when appropriate. JAE now requires the reporting of effect size when reporting statistical significance in quantitative manuscripts. The purposes of this manuscript are to describe the research foundation supporting the reporting of effect size in quantitative research and to provide examples of how to calculate effect size for some of the most common statistical analyses utilized in agricultural education research. Recommendations for appropriate effect size measures and interpretation are included. The assumptions and limitations inherent in the reporting of effect size in research are also incorporated.