This is exactly the intuition behind Cohen’s d — the standard unit of comparison for meta-analysis. You take the mean difference between the treatment group and

This is exactly the intuition behind Cohen’s d — the standard unit of comparison for meta-analysis. You take the mean difference between the treatment group and the control group, and divide that number by the standard deviation of the dependent variable, and then assess that result in many studies to see which treatment, or class of treatments, moved the needle the most.