Consent Process

When designing a study, the investigator should think about consent as a process with four elements: informing, assessment of comprehension, assessment of autonomy, and consent. The process of consent should also always be viewed as ongoing, potentially repeating itself throughout the subject’s participation. The consent process does not simply cease after one or more sessions in which the consent document is explained and signed. New information regarding a study’s risks and anticipated benefits may arise during the study, and this may impact a subject’s willingness to continue participating. The subject may have questions as the study progresses, affecting their continued participation. New information must be conveyed to subjects as it develops, and consent must be renewed. The consent document is also not a static contract. This form may need to be amended as new information about the study is exchanged between the investigator and the subject. It is essential that the dialogue or information exchange between the investigator and the subject continue throughout, and sometimes after, the study. The process of consent utilized by the investigator must be fully explained in the Institutional Review Board (IRB) protocol application, in the section titled “Process of Consent.” For further information, see DHHS Office for Human Research Protections (OHRP) IRB guidebook.

The first element in the process of consent is informing, and this involves two components-an oral explanation by the investigator, answering questions and concerns of  the subject, and the presentation of this information in a “consent form.” The consent form is presented following the verbal explanation so that the subject may refer to the document and have the opportunity to share it with family„friends or others while making his or her decision regarding participation. This element of the process should be viewed as an educational interchange between the subject and the investigator, intended to facilitate the subject’s comprehension of the study’s procedures, risks, and potential benefits. The methods used to convey information, the environment in which it is conveyed, as well as the mental state of the potential subject all impact the subject’s ability to assimilate the information.  The consent process should occur in a physical space that offers privacy, and in an atmosphere that encourages questions by the potential subject. The protocol should identify the circumstances under which the consent process will take place including the timing, the place, and the personnel involved. The verbal presentation by the investigator should be in language understandable to the subject or the subject’s representative; it should be organized, and it should provide the potential subject with sufficient time to ask questions.

The investigator may want to schedule more than one session to explain the research, particularly for complex or higher-risk studies that may be difficult for potential participants to understand, This will allow the potential subject an opportunity to consider the information presented and formulate questions. In these situations, subjects will often be given the information and the consent form at the initial meeting and be encouraged to discuss the information with their friends and family members or advisors, so that during a subsequent visit they will have the chance to clarify information, ask questions and, if ready, make a decision regarding participation. When attempting to convey complex information, investigators may use additional educational materials, such as audiovisual aids. In some situations it may also be appropriate to invite potential subjects to visit the actual research unit or setting and to demonstrate actual routines and procedures for them.

As a general rule, it is preferable to obtain consent from subjects in advance of invasive procedures (not on the day of the procedure). Subjects may be too nervous to comprehend or assimilate the information on the day of the procedure, and they may feel pressured by the investigator to make a decision on the spot.  In addition, the subject should be reminded of his or her right to withdraw just before the research procedure or intervention is initiated.

The content to be conveyed to potential subjects concerning informed consent is described in federal regulations. However, in general, the investigator should be sure to include all information that a “reasonable volunteer” who would not benefit directly from participation would want to know in order to make a decision about participation in a research project. The legal standard that has most commonly been applied is that of the “reasonable person” or the “prudent patient,” meaning that the information provided would be enough for a rational and sensible individual to make an “intelligent choice.”

The second element in the process of consent is assessment of comprehension. It can be difficult or even impossible to fully assess whether a potential subject has understood the information presented. One can only inform prospective subjects as clearly as possible and then conduct simple assessments of their understanding of the study procedures, risks, and benefits. The nature of the potential subject’s questions, as well as his or her answers to the investigator’s questions, will allow the investigator to assess comprehension. Subjects should always be asked questions about the study in a nonthreatening manner. Many consent forms include short summaries of the consent information or a list of sample questions that can assist the investigator in evaluating the potential subject’s comprehension. If subjects have difficulty assimilating the information despite simplification of the language and a thorough explanation of the information, the investigator should consider the use of an audiovisual aid. A short quiz, which might be part of the consent form, is also used by some investigators to assess comprehension.  Subjects who are unable to comprehend the information necessary for informed participation in the study should not be enrolled.

The third element in the process of consent is assessment of autonomy. No one can guarantee that another’s choice is voluntary. One can only attempt to remove obvious impediments to free choice. Investigators must attempt to remove any impediments to the autonomy of the prospective subject during the consent process by beginning with a clear invitation to participate, ensuring that the subject is free of coercion (any overt threat of harm or oppression) and undue influence or inducement (the desire to please a third a party or the offer or promise of excessive or inappropriate rewards). For example, when the consent process involves a potential subject who is either a patient or a student of the researcher, the investigator might include an impartial observer or ask another researcher or research associate involved with the project to obtain consent for the study. The investigator or person responsible for obtaining consent must always make it clear to the potential subject that he or she is free to decline or withdraw from the study at any time without negative repercussions.

The fourth element in the process of consent is obtaining the subjects agreement to participate. Only after the first three elements of the consent process have been satisfied, i.e., the potential subject has been fully informed, his or her comprehension has been deemed adequate, and his or her choice deemed voluntary, is the prospective subject asked to consent to participating in the study. This is typically accomplished by having the subject sign the consent document. The signed consent form is formal documentation attesting to the fact that the subject was properly informed and agreed to participate.  As stated earlier, a signed consent document does not mean that the process is completed.  The signed consent document signals the willingness of the subject to participate, with the expectation by both the subject and the investigator that the process of informed consent will continue.

For recommendations regarding the process of consent for those subjects with diminished capacity, see Module 7.

There are certain situations in which some or all of the elements of consent, or the documentation of informed consent, may be waived by the IRB. The waiver of informed consent and the waiver of the documentation of informed consent are two different types of waivers based upon different federal regulations. These types of waivers will be discussed in the Specific Guidance on Special Issues section of this module. 

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