🧬 Clinical Trial Statistics
Sample Size Calculator (Clinical Trials)
Calculate the required sample size for clinical trials and comparative studies. Supports two-proportion (binary outcomes) and two-mean (continuous outcomes) designs, aligned with ICH E9 Statistical Principles.
Study Design Parameters
Two Proportions
Compare % responders / event rates (binary outcomes). e.g. cure rate, AE rate.
Two Means
Compare continuous outcomes between two groups. e.g. HbA1c change, biomarker level.
0.05
Typical: 0.05 (two-sided) or 0.025 (one-sided)
0.80
80% or 90% typical for pharma trials
e.g. 0.60 = 60% response rate (control)
e.g. 0.80 = 80% response rate (treatment)
1 = equal allocation (most efficient)
Inflates n to account for dropouts
Results
Enter study parameters to calculate required sample size
Regulatory Reference (ICH E9): Standard pharmaceutical trial parameters: α = 0.05 (two-sided), power ≥ 80%. Increase sample size by 10–20% for anticipated dropouts. Consult a biostatistician for confirmatory trials.
Reference: ICH E9 Statistical Principles for Clinical Trials; FDA Guidance on Adaptive Designs (2019)