Establishing new cutoffs for Cohen's d: An application using known effect sizes from trials for improving sleep quality on composite mental health.

new cutoffs for effect size distribution of -0.177, -0.329, and -0.557, for small, medium, and large effect size were found, respectively. applying Cohen's effect size thresholds (0.2, 0.5, and 0.8) for trials of improving sleep quality on composite mental health might over-estimate effect sizes compared to the real-world context, especially around medium and large effect sizes.