STUDY DESIGN
Sample size, with the assumptions in full view.
Start in plain language or use the manual calculator. Statif shows the formula, adjustment path and design assumptions behind the answer.
Statif study design assistant
It extracts common design parameters from your prompt, fills the deterministic calculator and exposes the exact method used.
No invented study parameters
Every input remains editable
Signed-in calculations can be stored securely
Describe the outcome, study design, confidence, power, detectable difference and expected attrition. I will translate them into the calculator below.
Manual calculator
Change any entry, then calculate again.
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RECOMMENDED TOTAL
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participants
Run the assistant or manual form to see the calculation.
Planning estimate, not protocol approval
Rare outcomes, survival analysis, repeated measures, multilevel models, non-inferiority designs and multiplicity may require simulation or specialist review.
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