Your Easy Guide to Clinical Studies

An Estimand is a precise, detailed description of a study treatment (e.g. to whom and under what circumstances). It defines the exact research question the study intends to answer.

 

Example: a study assesses the effect of talking therapy on stress. Participants may decide to take additional medication, such as anxiolytics. Anxiolytics intake is therefore an Intercurrent Event (ICE) affecting study outcome and interpretation.

 

Researchers may decide to use a:

• Treatment policy Estimand: the ICE is ignored (corresponds to the intention-to-treat (ITT) principle). Treatment effect is assessed regardless of ICE occurrence, which is seen as real-world treatment experience?
• Hypothetical Estimand: the treatment effect is estimated under the hypothetical scenario that the ICE does not occur (e.g. participant stops treatment). What would outcome have been had the treatment continued?
• While on treatment Estimand: the treatment effect is estimated prior to ICE occurrence (e.g. therapy effect up to the initiation of additional medication)
• Principal stratum Estimand: the treatment effect is estimated in participants without ICE (e.g. in participants who did not initiate additional medication)

As a SP-INV, decide which question is most useful and therefore which Estimand strategy should be used. A slightly different research question may lead to a different study conclusion.

SCTO Research Tools & Resources

• SCTO Statistic Platform

Video

• What are Estimands