Glass's delta

Glass's delta is a statistical measure used in the field of psychology and education to quantify the size of an effect or the strength of a difference between two groups. Specifically, it shows how much an intervention changes outcomes compared to a control group. Unlike other measures, Glass’s delta uses the standard deviation of the control group as the denominator, making it useful when you want to assess the impact of a treatment while controlling for variability in the control group’s performance. It helps researchers understand the practical significance of their findings more clearly.