Quantum mechanics

Algorithm

Statistics

Surgery

Rule of thumb

Computer science

Thermodynamics

Physics

Thumb

Mathematics

Sample size determination

Medicine

Sample (material)

Group (periodic table)

Pharmaceutical Statistics

When designing a clinical trial an appropriate justification for the sample size should be provided in the protocol. However, there are a number of settings when undertaking a pilot trial when there is no prior information to base a sample size on. For such pilot studies the recommendation is a sample size of 12 per group. The justifications for this sample size are based on rationale about feasibility; precision about the mean and variance; and regulatory considerations. The context of the justifications are that future studies will use the information from the pilot in their design. Copyright © 2005 John Wiley & Sons, Ltd.

Sample size of 12 per group rule of thumb for a pilot study