Explicit consent. Participants give consent by answering a specific question about their willingness to participate. This may be done in written (consent form) or oral form.
To be informed, consent must be given by persons who are competent to consent, have consented voluntarily, are fully informed about the research, and have comprehended what they have been told. Unless they are emancipated minors, individuals under 18 may never give consent. Also question the legal competence of people affected by mental illness, or institutionalized in the prison system. If a person is not legally competent to give consent, a parent or legal guardian has to give it. The participant may still give assent.
To guarantee that participants understand what they are consenting to, researchers should pay attention to the language they use. They should use the language that their target population will be most comfortable with. As a rule, they should refrain from using technical language and use an 8thgrade level of English. Depending on the methodology you are using, the population and topic you are studying, and the level of risk, informed consent may be implied or explicit, active or passive, and written or oral.
Some participants, although not legally competent, are able to make judgment about their participation themselves. This is the case for teenagers and some mentally impaired individuals, for instance. The assent formgives them an opportunity to express their agreement to participate in research in writing, beyond the consent given by a legal guardian or parent. Although the assent is not legally binding, and does not dispense a researcher from obtaining consent from a parent or legal guardian, it is advisable as sound ethical practice. It reinforces the voluntary nature of participation.