Investigators must include in their protocols a data and safety monitoring plan that describes how the safety of their subjects (in relation to unanticipated or adverse events) will be monitored and how adverse events will be reported. Some of these plans, typically those for larger studies involving DSMCs, also monitor efficacy data to determine the likelihood that the study will lead to a statistically valid result or generalizable knowledge. The complexity of these plans will vary with the type of research conducted, the complexity of the study (e.g., the number of sites involved), and the potential harm faced by subjects. The simplest of these plans will be carried out completely by the investigator. The most complex plans, such as those associated with double-blind randomized clinical trials, will involve special DSMCs that oversee these monitoring functions and make regular reports to the trial’s steering committee and grant sponsors who may, in turn, report adverse event information to IRBs and investigators. Each protocol must define who (what individual or group) will take the primary responsibility for analyzing individual events to determine if the study should be modified to minimize risk to current or future research subjects. More information on the following topics can be found at the links in the box at right.