Determining sample size for pilot trials: a tutorial
Pilot trials have a key role in preparing for definitive randomized trials, yet determining their sample size remains a common challenge. This article provides practical guidance, methods, and tools—including step-by-step examples, sample size tables, and statistical code—for calculating and justifying sample sizes in external randomized pilot trials.
Authors
- Xiangji Ying (ORCID: https://orcid.org/0000-0002-1713-3788)
- Lynda H. Powell (ORCID: https://orcid.org/0000-0002-3527-8227)
- Kenneth E. Freedland (ORCID: https://orcid.org/0000-0002-3118-9913)
- Stephan Ehrhardt
- Evan Mayo‐Wilson (ORCID: https://orcid.org/0000-0001-6126-2459)
- Elizabeth A. Stuart (ORCID: https://orcid.org/0000-0002-9042-8611)
Institutions
- University of North Carolina at Chapel Hill (US)
- Rush University Medical Center (US)
- Johns Hopkins University (US)
- Washington University in St. Louis (US)
Publication Details
- Journal
- BMJ
- Published
- 2025-08-08
- DOI
- https://doi.org/10.1136/bmj-2024-083405
- Citations
- 19
- Primary Topic
- Meta-analysis and systematic reviews
- Type
- article
- Field-Weighted Citation Impact
- 26.57