The Ottawa Statement on the ethical design and conduct of cluster randomised trials: precis for researchers and research ethics committees.

Cluster randomised trials have unique features that complicate the application of standard ethics guidelines for research. The Ottawa Statement on the ethical design and conduct of cluster randomised trials was developed to provide detailed guidance to researchers, research ethics committees, regulators, and sponsors as they seek to fulfil their respective roles.This article describes the development of the Ottawa Statement and outlines key implications for researchers and research ethics committees.