Measurable changes in health monitored during a clinical trial to assess the efficacy and safety of an intervention.

Outcomes can be either positive (e.g. cure, survival) or negative (e.g. death). Choice of outcome measure is a critical aspect of clinical trial design. They must provide a reliable and meaningful measure of the impact of an intervention. Ideally, they are widely accepted and used measures, facilitating pooled analysis of data from multiple studies.

It is important to ensure that outcome measures are considered appropriate by regulatory authorities. Discussion with such authorities may be necessary in advance of trials to determine which outcome measures would be acceptable.

Endpoints are specific outcome values, used to assess whether an intervention has had a clinically meaningful impact.