What is an estimand?

Published

January 5, 2026

What is an estimand?

From the glossary of the ICH E9: estimands addendum:

A precise description of the treatment effect reflecting the clinical question posed by the trial objective. It summarises at a population-level what the outcomes would be in the same patients under different treatment conditions being compared.

Where should I start?

The trainings page is a starting point. Further, a 3min intro video is available: What is an estimand in a clinical trial: The PIONEER 1 example.

See also the publications page regarding work from the EIWG. Recently, members of the EIWG have prepared topics on ICH E9(R1) requiring further clarification.