What is the difference between Cohen's d and Hedges' g?

Cohen's d calculates the standardized mean difference, while Hedges' g applies a correction factor that provides a less biased estimate for small sample sizes (typically under 20).

How do I interpret the magnitude of the effect size?

The tool automatically provides a magnitude label based on standard statistical conventions, such as 0.2 for small, 0.5 for medium, and 0.8 for large effects in Cohen's d.

Can I calculate effect sizes without raw data?

Yes, this calculator is specifically designed to work with summary statistics like means, standard deviations, and sample sizes, requiring no raw dataset.

What is Cohen's h used for?

Cohen's h is used to measure the effect size between two independent proportions, helping to determine if the difference between two rates or percentages is practically meaningful.

How many decimal places can I calculate?

You can configure the output precision from 0 up to 10 decimal places using the decimal places setting.

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Effect Size Calculator

Calculate Cohen d, Hedges g, Cohen h for proportions, or correlation r effect sizes from summary statistics

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Calculate Cohen d from two group summaries

Compare two group means using pooled standard deviation to estimate standardized effect size

{"result":{"effectSize":0.3333,"magnitude":"small","metric":"Cohen d"}}

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Effect TypeselectOptionalGroup 1 MeannumberOptionalGroup 2 MeannumberOptionalGroup 1 Standard DeviationnumberOptionalGroup 2 Standard DeviationnumberOptionalGroup 1 SizenumberOptionalGroup 2 SizenumberOptionalProportion 1numberOptionalProportion 2numberOptionalCorrelationnumberOptionalDecimal PlacesnumberOptional

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