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Table 1 Ottawa Statement on the ethical design and conduct of cluster randomized trials: summary of recommendations

From: Ethical issues in cluster randomized trials conducted in low- and middle-income countries: an analysis of two case studies

Number Ethical issue Recommendation
1 Justifying the cluster randomized design Researchers should provide a clear rationale for the use of the cluster randomized design and adopt statistical methods appropriate for this design
2 REC review Researchers must submit a CRT involving human research participants for approval by an REC before commencing
3 Identifying research participants Researchers should clearly identify the research participants in CRTs. A research participant can be identified as an individual whose interests may be affected as a result of study interventions or data collection procedures; that is, an individual:
1) who is the intended recipient of an experimental (or control) intervention; or
2) who is the direct target of an experimental (or control) manipulation of his/her environment; or
3) with whom an investigator interacts for the purpose of collecting data about that individual; or
4) about whom an investigator obtains identifiable private information for the purpose of collecting data about that individual.
Unless one or more of these criteria is met, an individual is not a research participant
4 Obtaining informed consent Researchers must obtain informed consent from human research participants in a CRT, unless a waiver of consent is granted by an REC under specific circumstances
5   When participants’ informed consent is required, but recruitment of participants is not possible before randomization of clusters, researchers must seek participants’ consent for trial enrollment as soon as possible after cluster randomization—that is, as soon as the potential participant has been identified, but before the participant has undergone any study interventions or data collection procedures
6   An REC may approve a waiver or alteration of consent requirements when 1) the research is not feasible without a waiver or alteration of consent and 2) the study interventions and data collection procedures pose no more than minimal risk
7   Researchers must obtain informed consent from professionals or other service providers who are research participants unless conditions for a waiver or alteration of consent are met
8 Gatekeepers Gatekeepers should not provide proxy consent on behalf of individuals in their cluster
9   When a CRT may substantially affect cluster or organizational interests, and a gatekeeper possesses the legitimate authority to make decisions on its behalf, the researcher should obtain the gatekeeper’s permission to enroll the cluster or organization in the trial. Such permission does not replace the need for the informed consent of research participants
10   When CRT interventions may substantially affect cluster interests, researchers should seek to protect cluster interests through cluster consultation to inform study design, conduct and reporting. Where relevant, gatekeepers can often facilitate such a consultation
11 Assessing benefits and harms The researcher must ensure that the study intervention is adequately justified. The benefits and harms of the study intervention must be consistent with competent practice in the field of study relevant to the CRT
12   Researchers must adequately justify the choice of the control condition. When the control arm is usual practice or no treatment, individuals in the control arm must not be deprived of effective care or programs to which they would have access were there no trial
13   Researchers must ensure that data collection procedures are adequately justified. The risks of data collection procedures must 1) be minimized consistent with sound design and 2) stand in reasonable relation to the knowledge to be gained
14 Protecting vulnerable participants Clusters may contain some vulnerable participants. In these circumstances, researchers and RECs must consider whether additional protections are needed
15   When individual informed consent is required, and there are individuals who may be less able to choose participation freely because of their position in a cluster or organizational hierarchy, RECs should pay special attention to recruitment, privacy and consent procedures for those participants
  1. CRT cluster randomized trial, REC research ethics committee