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.
Oral consent should be considered when obtaining explicit, active consent is essential, but the risk or discomfort involved in the process is too great to make written consent a valid option. Some populations, such as criminals, undocumented immigrants, or the homeless, may be placed at legal risk, or be suspicious of leaving a written trace, and refuse to participate. Or, the topic of the research may be highly sensitive, because it concerns behavior and attitudes that, even though legal, are socially condemned. Should the records be exposed, or a criminal investigation take place, researchers themselves may become liable. Oral consent is also a valid option for participants that are uncomfortable reading and writing, and may be too embarrassed by the written consent process to participate in research. In that case, the researcher should record the reading of a consent statement, and the clear answers of the participants indicating willingness to participate. The recording verifies informed oral consent.
Written consent. Participants give their consent by filling out a consent form. Written consent guarantees active and explicit consent, thus offering the highest guarantees to the participant. It is most appropriate in studies that contain some level of risk, but also in many studies with no risk above those of daily life, when participants disclose personal or sensitive information, when they are exposed to deception, or any experimental treatment. Experiments and in-depth interviews in particular should consider written consent.
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.