informed consent
a person’s voluntary agreement to participate in a procedure on the basis of his or her understanding of its nature, its potential benefits and possible risks, and available alternatives. Informed consent is a fundamental requirement of research with humans and typically involves having participants sign documents, prior to the start of a study, that describe specifically what their involvement would entail and noting that they are free to decline participation or to withdraw from the research at any time. In therapeutic contexts, the principle of informed consent has provided a foundation for do not resuscitate (DNR) orders and other advance directives and for the natural-death acts that have been passed into law throughout the United States. See also institutional review board.