A sample-size justification reviewers cannot pick apart.

Sample size & power calculation

What you get, and how it runs.

The calculation, the assumptions behind it, and where each assumption came from, written so that an ethics committee, a grant reviewer, or a journal referee can follow and reproduce it. Delivered with the code, so it can be re-run if the design changes.

How it works

1. You tell us the primary outcome, the comparison, and the design.
2. We source the effect size and variability from the literature or your pilot data, and state the choice.
3. We calculate the required sample, with sensitivity to the key assumptions and allowance for dropout or clustering.
4. You receive the written justification paragraph, ready to paste into the protocol or grant.