Experimental Design and Power

Cohen H Effect Size Calculator

Calculates Cohen’s h for a difference between two proportions. The form displays 2asin(sqrt(p1))−2asin(sqrt(p2)) beside cohen h effect size, using a worked condition that can be recalculated with the labeled inputs.

Design and power inputs

Set the labeled inputs

proportion
proportion
Calculated result

Cohen H Effect Size

Result
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2asin(sqrt(p1))−2asin(sqrt(p2))

    Interpreting the requested cohen h effect size

    The cohen h effect size page calculates Cohen’s h for a difference between two proportions.

    Cohen H Effect Size is limited to the statistical quantity named by the result panel. The cohen h effect size calculation does not silently add a population, time horizon, causal direction, or decision threshold that is absent from the fields.

    How the inputs shape cohen h effect size

    • Proportion 1: For cohen h effect size, the worked value for proportion 1 is 0.6 proportion. Treat the proportion 1 entry (0.6 proportion) explicitly as a count, proportion, rate, estimate, or model parameter before comparing cohen h effect size conditions. The form enforces minimum 1e-06, maximum 0.999999.
    • Proportion 2: For cohen h effect size, the worked value for proportion 2 is 0.4 proportion. Treat the proportion 2 entry (0.4 proportion) explicitly as a count, proportion, rate, estimate, or model parameter before comparing cohen h effect size conditions. The form enforces minimum 1e-06, maximum 0.999999.

    The entries used for cohen h effect size must refer to one coherent analysis condition. Combining incompatible populations, periods, or measurement definitions can produce valid cohen h effect size arithmetic for a nonexistent study.

    Working through the cohen h effect size formula

    2asin(sqrt(p1))−2asin(sqrt(p2))

    For cohen h effect size, match every symbol in the relationship to a labeled field before substituting numbers. Cohen H Effect Size is reported in the scale implied by the inputs and formula.

    While checking cohen h effect size, the domain restrictions in 2asin(sqrt(p1))−2asin(sqrt(p2)) matter: logarithms and roots cannot accept every real-number input.

    Worked values for cohen h effect size

    The default cohen h effect size condition is Proportion 1 = 0.6 proportion, Proportion 2 = 0.4 proportion.

    Proportions .60 and .40 give Cohen h about 0.403.

    The live calculator reports Cohen h 0.40271584. Repeating one intermediate step from 2asin(sqrt(p1))−2asin(sqrt(p2)) provides a fixed cohen h effect size reference check for later code changes.

    Limits on interpreting cohen h effect size

    The arcsine transformation makes the scale distinct from a raw percentage-point difference.

    For cohen h effect size, power and design calculations are prospective scenarios, not guarantees. For cohen h effect size, their answer changes when the planned effect, variance, allocation, alpha, or attrition assumption changes.

    How to interpret the cohen h effect size output

    When interpreting cohen h effect size, report the design inputs as assumptions and compare at least one plausible alternative before committing resources to the plan.

    As a second check for cohen h effect size, test a boundary value for Proportion 1 before relying on software that silently clips, transforms, or discards an invalid observation.

    A reproducible record of cohen h effect size

    Report cohen h effect size using 2asin(sqrt(p1))−2asin(sqrt(p2)), followed by the entered values, units, exclusions, and analysis date. Name the cohen h effect size population or dataset boundary instead of leaving it implicit.

    Keep the full calculator output with the record, including Cohen h 0.40271584. A later cohen h effect size review can then distinguish a changed input from a different convention or software implementation.

    Questions about cohen h effect size

    What does cohen h effect size represent on this page?

    It is the quantity produced by 2asin(sqrt(p1))−2asin(sqrt(p2)) from the displayed proportion 1, proportion 2. This page calculates Cohen’s h for a difference between two proportions.

    What should be saved with cohen h effect size?

    Save the entered values and units for proportion 1, proportion 2, along with the analysis date, exclusions, software or formula version, and the relationship 2asin(sqrt(p1))−2asin(sqrt(p2)). That record is sufficient to rebuild this specific cohen h effect size calculation.

    Does cohen h effect size establish a causal or population conclusion?

    No. The displayed cohen h effect size value is conditional on the entered data and named method. The cohen h effect size design, measurement process, and assumptions determine what can be concluded beyond those values.

    How should cohen h effect size be rounded?

    Keep the unrounded cohen h effect size for subsequent arithmetic, then report only the precision supported by the source measurements and the decision context. Extra digits in cohen h effect size do not correct sampling or model error.

    Which input deserves the closest boundary check?

    For cohen h effect size, start with proportion 2 and then proportion 1. Confirm the cohen h effect size units and allowed domain because a valid-looking entry can still describe the wrong statistical setup.