Transformed Vargha-Delaney effect size

Abstract

Researchers without a technical background in statistics may be tempted to apply analytical techniques in a ritualistic manner. SBSE research is not immune to this problem. We argue that emerging rituals surrounding the use of the Vargha-Delaney effect size statistic may pose serious threats to the scientific validity of the findings. We believe investigations of effect size are important, but more care is required in the application of this statistic. In this paper, we illustrate the problems that can arise, and give guidelines for avoiding them, by applying a ‘transformed’ Vargha-Delaney effect size measurement. We argue that researchers should always consider which transformation is best suited to their problem domain before calculating the Vargha-Delaney statistic.