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# Guide on Drug Statistical Principles for Clinical Trials
- URL: https://www.fdaweb.com/guide-on-drug-statistical-principles-for-clinical-trials/
- Published: 2021-05-12T12:00:00.000Z
- Updated: 2026-09-14T16:58:39.000Z
- Author: David McFarland
- Tags: FDA Policy/General, #legacy-id-D5149301

*Federal Register* notice: FDA is making available a final guidance entitled *E9(R1) Statistical Principles for Clinical Trials: Addendum: Estimands and Sensitivity Analysis in Clinical Trials*. The guidance was prepared under the auspices of the International Council for Harmonization to clarify, update, and extend a 1998 guidance entitled *E9 Statistical Principles for Clinical Trials.* Concerning estimands, it provides a framework for discussion of how the aims of a trial relate to the proposed statistical analysis. Concerning sensitivity analysis, it discusses how to use additional analyses to address concerns about the validity of assumptions underlying the main analysis. To view the notice, click [here](https://www.govinfo.gov/content/pkg/FR-2021-05-12/pdf/2021-10066.pdf?ref=fdaweb.com).