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Sample Size Calculators
for designing clinical research
Need help? Request a consultation from sample-size.net developer Michael Kohn about sample size calculation, study design, data management, or statistical analysis.
Sample Size Calculators
If you are a clinical researcher trying to determine how many subjects to include in your study or you have another question related to sample size or power calculations, we developed this website for you. Our approach is based on Chapters 5 and 6 in the 4th edition of Designing Clinical Research (DCR-4), but the material and calculators provided here go well beyond an introductory textbook on clinical research methods.