Investigators must include in their protocols a thorough description of the population from which subjects will be drawn. This population is selected for inclusion because its attributes make it possible to accomplish the purpose of the research. Each protocol must contain inclusion criteria, criteria that prospective subjects must have to be included in the study, and exclusion criteria, criteria that disqualify prospective subjects from participation. No group should be excluded from participation unless there is good reason to do so (e.g., they are at greater risk). Vulnerable subjects, or subjects with reduced decision-making capacity, may be at greater risk and if they are to be included, the protocol must contain additional safeguards. Finally, subjects must be recruited and protocols must clearly describe how potential subjects will be identified, the method of contact, and who will be contacting them. More information on the following topics can be found at the links in the box at right.