Nvolve the protection of individual interests.Gatekeeper authority to protect cluster interestsThe wide variety of groups studied in CRTs presents a challenge to those trying to determine who has legitimate authority to represent and protect the interests of a cluster. CRTs may involve a variety of clusters, withGallo et al. Trials 2012, 13:116 http://www.trialsjournal.com/content/13/1/Page 9 ofva