Definition

A system developed by the WHO Uppsala Monitoring Centre using clinical judgment to classify causality as certain, probable/likely, possible, unlikely, conditional, or unassessable.

Example

Using WHO-UMC criteria: Certain = positive rechallenge; Probable = reasonable time, positive dechallenge, unlikely alternative; Possible = reasonable time but alternative explanations exist.

Regulatory source

WHO-UMC Guidelines

Common mistakes

Confusing 'conditional' (awaiting more data) with 'unassessable' (insufficient data to assess).

Inspector question

What causality categories do you use? How do you reconcile differences between company and reporter assessments?

Related terms