The concept of vulnerability means something different in an IRB context than it does in the common usage of the term: a vulnerable participant is someone who, 由于个人限制, 组成员, 或者他们所处的情况, might not be completely free to refuse to participate in a re搜索 study because they have reduced capacity to make decisions for themselves. Vulnerability in this sense is important because if a person is not completely free to refuse to participate in re搜索, in a sense they cannot give meaningful consent or assent to participate either. Vulnerability is thus tied to the "voluntariness" aspect of consent.

Vulnerability can also be tied to the "comprehension" aspect of consent. In order to weigh one's participation-related options fully, one must understand both the probability and the likely magnitude of potential harm along with other kinds of information about the re搜索 experience. Even if information about the re搜索 is presented in a comprehensible way, someone who does not comprehend the information cannot freely consent to participate in the re搜索, since they do not understand that to which they are consenting. 

We may talk of vulnerable individuals or vulnerable populations, 但无论哪种情况, the vulnerability is often due to one of the following conditions/situations (described in a document previously available from the University of Virginia):

1)认知或交际(e).g., a mental or language barrier; someone who does not speak English or is educationally disadvantaged, or is a child and thus not mature enough to understand the nature of the re搜索, or is a developmentally delayed or mentally ill adult and thus in the same circumstance). 在一个单独的子页上讨论了儿童. 没有认知或沟通障碍的人, but who is in an emotional state where they are not able to think clearly about or advocate for their own interests, 也可以属于这一类吗. Someone may also fall into this category if the voluntariness and comprehension conditions are met but the person is unable to express their choice about participating effectively for some reason.

2) Institutional (a student participating in a professor's re搜索 or an employee in an employer's re搜索; in this instance, the re搜索er has power over the potential participant and could theoretically use that power in retribution if the potential participant elected not to participate; similar reasoning is used in describing prisoners, 住院病人, and other institutionalized people such as the elderly (in some cases) as vulnerable)

3) Deferential (the re搜索er is a doctor and the potential participant is a patient, or the re搜索er is a senior family member; in these circumstances, the re搜索er is generally treated with special respect and deference and it is presumed that they will get their wishes)

4) Medical (the potential participant has a serious or terminal illness and thus has a medical need that they can only get met by participating in the re搜索; alternately, a person who is depressed or otherwise emotionally upset as a result of their medical situation may not have the capacity to act in their own best interests). 

5)经济(潜在参与者贫穷), 无家可归的人, or otherwise economically disadvantaged and the incentives to participate (free resources) would make such a difference in the person's life or well-being as to have a coercive effect). The issue of incentives is discussed on a separate subpage.

6) Social (a person is a member of a social group that faces real or perceived discrimination and thus is unusually vulnerable to coercion in a re搜索 context). 无证移民, 例如, may face a legal threat if they refuse to participate in re搜索. 

囚犯, 特别是, require special review on the part of the IRB including the presence of a prisoner representative during the Full Board review of the re搜索. 囚犯代表可以包括一名前囚犯, 有照顾囚犯经验的社会工作者, 公设辩护律师, 监狱牧师, 或者是另一种被普遍接受的类型的倡导者. 学生 may only pursue re搜索 involving prisoners as part of a project for which a faculty or staff member is the principal investigator. 教师 and staff are advised that such projects will call for a slow review process compared to our traditionally efficient turnaround.

Additional guidance on re搜索 with prisoners is available from the government.

特别是在生物医学研究方面, pregnant women and fetuses are federally defined as vulnerable but this situation of vulnerability is not discussed here because 科罗拉多大学 re搜索ers do not currently carry out biomedical re搜索 involving pregnant women or fetuses.

None of the above points should be taken to mean that someone with one of the above identities or in one of the above situations can never participate in re搜索, only that they are to receive special protections to make sure that they do in fact consent, 没有被强迫过, and understand clearly what participation in the re搜索 entails.