In cluster randomised trials (CRT), groups (rather than individuals) are randomised to intervention and control conditions. Since the publication of the Ottawa Statement on the Ethical Design and Conduct of CRTs, the accurate identification of research participants has continued to challenge researchers and research ethics committees.

In this article, we focus on CRTs involving healthcare providers and provide a practical framework for applying Ottawa Statement criteria for identifying research participants. We illustrate key lessons with example CRTs.

Study procedures should be analysed in relation to the study objective. A study intervention confers research participant status on healthcare providers if the study objective is to evaluate its effect and it is delivered to or targeted at healthcare providers. A data collection procedure confers research participant status on healthcare providers if it informs a study outcome used to achieve the study objective and it involves interactions between researchers and healthcare providers to collect their data, or the collection of healthcare providers’ identifiable private information.

In CRTs, healthcare providers may be research participants because of study interventions, data collection procedures, or both; conversely, they may simply be research collaborators. Some study interventions confer research participant status on both healthcare providers and patients. Collecting data on healthcare provider behaviour may confer research participant status on healthcare providers.

Accurately identifying research participants in CRTs is essential to their ethical conduct. When healthcare providers are research participants, their rights and welfare should be protected in accordance with research ethics guidelines.