Comparative Study Sample Size Calculator

Calculate sample sizes for case-control and cohort studies with comprehensive analysis

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Upload study protocol to auto-extract case-control parameters

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Statistical Parameters

Standard parameters for case-control study design

Significance Level (α) (%)

Type I error rate - probability of false positive (typically 5%)

💡 Example: 5 for p < 0.05 (standard)

Statistical Power (%)

Probability of detecting a true effect (80-90% recommended)

💡 Example: 80 for 80% power (standard)

Case-Control Study Parameters

Specific parameters for retrospective case-control study design

Allocation Ratio

Number of controls recruited per case. Higher ratios increase power but also cost.

💡 Example: 1 for 1:1 randomization

Exposure Rate in Controls

Expected proportion of controls with exposure history (baseline exposure rate)

💡 Example: 50.0 for 50%

Exposure Rate in Cases

Expected proportion of cases with exposure history (should be higher than controls)

💡 Example: 50.0 for 50%