Capacity + Competence to Consent


Capacity is the ability of prospective or actual participants to understand relevant information presented (e.g. purpose of the research, foreseeable risks, and potential benefits), and to appreciate the potential consequences of any decision they make based upon this information.

The Tri-Council Policy Statement: Ethical Conduct for Research Involving Humans(TCPS2) states that a participant may have developing or diminished capacity, i.e. a minor or person with cognitive impairment, but still be able to decide whether to participate in certain types of research. If a potential research participant has the capacity to consent, consent must be sought from them before the research commences. If a person does not have the capacity to consent, they should still be involved in the consent process where possible and appropriate and given the opportunity to assent. If a person who lacks the capacity to consent declines to participate in research, his or her dissent must be respected and the person may not be included in the research.

The capacity to consent to research is not a static determination; it may vary over time, and upon the complexity and circumstances of the decision being made. It is the responsibility of the Principal Investigator (PI) to determine and monitor participants' capacity to consent and to describe this to the REB in the context of the proposed study. Where it is foreseeable that a participant may lose capacity during a research project, for example in studies of cognitive impairment, it may be appropriate to ask participants to express their preferences and ensure that they have authorized a trusted person to make decisions on their behalf should they lose the capacity to provide ongoing consent.

Assent, Dissent + Third-Party Consent on Behalf of Others

Many individuals who lack the capacity to make decisions may still be able to express their wishes in a meaningful way, even if such expression may not fulfill all of the requirements for consent. Prospective participants may be capable of verbally or physically assenting to, or dissenting from, participation in research.

Those who may be capable of assent or dissent include:

  1. those whose capacity is in the process of development, such as children whose capacity for judgment and self-direction is maturing;
  2. those who once were capable of making an autonomous decision regarding consent but whose capacity is diminishing or fluctuating; and
  3. those whose capacity remains only partially developed, such as those living with permanent cognitive impairment.

Where an authorized third party has consented on behalf of an individual who lacks legal capacity, but that person has some ability to understand the significance of the research, the researcher shall ascertain the wishes of that individual with respect to participation. While their assent would not be sufficient to permit them to participate in the absence of consent by an authorized third party, their expression of dissent or signs suggesting they do not wish to participate must be respected. Prospective participants' dissent will preclude their participation.

Where individuals have signed a research directive indicating their preferences about future participation in research in the event that they lose capacity or upon death, researchers and authorized third parties should be guided by these directives during the consent process.

Researchers should be aware of all applicable legal and regulatory requirements with respect to capacity. These may vary among jurisdictions. Authorized third parties who are asked to make a consent decision on behalf of a prospective participant should also be aware of their legal responsibilities.

The consent process must comply with the requirements of the TCPS2 and where appropriate, with the ICH Good Clinical Practice: Consolidated Guidelines, Section 4.8, Informed Consent of Trial Subjects.

For further information, see

Capacity for Children to Consent to Participate in Research

The legal age of majority in Alberta is 18. However, depending on the nature of the research, a participant may have the capacity to consent well before the age of majority. Alberta law does not specifically prevent a person under the age of majority from consenting to participate in research. The common law has two well accepted doctrines that are applicable to the consent of minors. The first is the "emancipated minor" doctrine, and the second is the "mature minor" doctrine.

The emancipated minor doctrine provides that persons under the age of majority who are "emancipated" in the sense of living on their own, earning their own income, etc. are generally capable of consent because they are "emancipated from parental control and guidance."

The mature minor doctrine is a common law rule that takes the varying abilities of young people into account and recognizes that some minors are able to make decisions for themselves. Generally, at common law, if a minor has reached a level of intellectual and emotional maturity such that he or she is capable of understanding and appreciating the nature and consequences of a particular treatment/decision, together with its alternatives they can be considered capable of consenting. Put another way, if it can be determined that a minor in fact understands the proposed interventions, can properly weigh the risks and benefits of various procedures, understands other courses of action and their implications, and is not prohibited from consenting by legislation, a minor may give a legally valid consent.

There is some debate concerning whether the mature minor doctrine applies in instances where treatment is not beneficial or therapeutic, but increasingly the "rights of minors" to decide are being recognized, except in the most extreme cases, e.g. life and death situations.

The ability to consent to research is not based upon on a participant's age or whether they have reached the age of majority. Generally, the threshold for recognition of maturity by the Courts is at least sixteen years and none have recognized any individual younger than fourteen years. In accordance with the TCPS2, the capacity to consent to research is premised upon an individual's ability to understand the nature of the research and the consequences of participation in the research project.

The Panel on Research Ethics (PRE) stresses that no two research studies or research participants are the same. Therefore, the researcher plays an important role in determining whether a particular research participant is capable of consenting on their own behalf or whether an authorized third party should be used. Within the same research project, there may be some minors who are capable of consenting and others who are not. The researcher should describe to the REB how the study team will determine the capacity to consent to the research for those proposed participants who are under the age of majority. The PRE advises that factors to consider in making the decision to seek consent from children should include the following: the level of risk the research may pose to participants, provincial legislation and other applicable legal and regulatory requirements related to the legal age of consent, and the characteristics of the intended research participants. In Alberta, this usually requires the attestation of a parent or healthcare provider or someone with significant knowledge of the child, such as a teacher.