Cohen's d is a statistical measure used to quantify the effect size between two groups. It indicates how many standard deviations the means of the two groups differ. A higher value of Cohen's d suggests a larger difference between the groups, making it easier to understand the practical significance of research findings. Typically, Cohen's d values are interpreted as small (0.2), medium (0.5), or large (0.8) effects. This measure is particularly useful in fields like psychology and education, where researchers often compare the effectiveness of different interventions or treatments, helping to convey the importance of their results beyond mere statistical significance.