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# ICH Guidance Addendum on Trial Statistical Principles
- URL: https://www.fdaweb.com/ich-guidance-addendum-on-trial-statistical-principles/
- Published: 2017-10-30T12:00:00.000Z
- Updated: 2026-09-14T22:58:54.000Z
- Author: David McFarland
- Tags: Drugs, #legacy-id-D5139993

FDA has published an International Council for Harmonization [guidance](https://www.fda.gov/downloads/Drugs/GuidanceComplianceRegulatoryInformation/Guidances/UCM582738.pdf?ref=fdaweb.com) entitled “E9 (R1) Statistical Principles for Clinical Trials: Addendum: Estimands and Sensitivity Analysis in Clinical Trials.” The addendum presents a structured framework to link trial objectives to a suitable trial design and tools for estimation and hypothesis testing. It introduces the concept of an estimand, “translating the trial objective into a precise definition of the treatment effect that is to be estimated.” Attributes of an estimand, according to the document, “include the population of interest, the variable (or endpoint) of interest, the specification of how intercurrent events are reflected in the scientific question of interest, and the population-level summary for the variable.”