TCPS 2 (2018) – Chapter 3: The Consent Process

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The TCPS 2 (2022) has replaced TCPS 2 (2018) as the official human research ethics policy of the Agencies.

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This chapter sets out the ethical requirements for consent in research involving humans. Throughout this Policy, the term “consent” means “free, informed and ongoing consent.” For the purpose of this Policy, “free” and “voluntary” are used interchangeably.

Respect for Persons implies that individuals who participate in research should do so voluntarily, understanding the purpose of the research, and its risks and potential benefits, as fully as reasonably possible. Where a person has the capacity to understand this information, and the ability to act on it voluntarily, the decision to participate is generally seen as an expression of autonomy. The Policy refers to the process of seeking consent from prospective participants, which may result in either agreement or refusal to participate. This process is meant to emphasize Respect for Persons. Under no circumstances may researchers proceed to conduct research with anyone who has refused to participate. Subject to exceptions set out in this Policy, consent must be obtained from participants prior to the conduct of research.

Equally, Respect for Persons implies that those who lack the capacity to decide for themselves should nevertheless have the opportunity to participate in research that may be of benefit to themselves or others. Authorized third parties acting on behalf of these individuals may decide whether participation would be appropriate. For the purposes of this Policy, the term “authorized third party” (also known as “authorized third party decision makers”) refers to any person with the necessary legal authority to make decisions on behalf of an individual who lacks the capacity to decide whether to participate or to continue to participate in a particular research project. These decisions involve considerations of Concern for Welfare and Justice.

Certain types of research require alternate processes for seeking consent. These are also described in this chapter. Researchers may request an alteration to consent requirements if they can meet the criteria of Article 3.7A. These include a requirement to satisfy the research ethics board (REB) that it is impossible, impracticable (see Glossary) or inappropriate to address the research question without the requested alteration. Where elements of the consent process may need to be adapted to the requirements of a particular research project, the REB can play an educational and consultative role in determining the appropriate process for seeking and maintaining consent. REBs must consider whether the requested alterations are justified or whether another approach would make it possible, practicable and appropriate to follow the normal consent requirements.

The head of the research team, also known as the “principal investigator”, is responsible for ensuring that the consent process is followed. This person is also responsible for the actions of any member of the research team involved in the consent process.

In addition to this Policy, researchers are responsible for ensuring that all applicable legal and regulatory requirements with respect to consent are met. In some circumstances, researchers may have further legal obligations that may be determined in part by the nature of the research and the jurisdiction in which the research is being conducted.Footnote 1

A. General Principles

Consent Shall Be Given Voluntarily

Article 3.1

  1. Consent shall be given voluntarily.
  2. Consent can be withdrawn at any time.
  3. If a participant withdraws consent, the participant can also request the withdrawal of their data or human biological materials.

(a) The voluntariness of consent is important because it respects human dignity and means that individuals have chosen to participate in research according to their own values, preferences and wishes.

The approach to recruitment is an important element in assuring voluntariness. In particular, how, when and where participants are approached and who recruits them are important elements in assuring (or undermining) voluntariness. In considering the voluntariness of consent, REBs and researchers should be cognizant of situations where undue influence, coercion or the offer of incentives may undermine the voluntariness of a participant’s consent to participate in research.

Undue influence

Undue influence and manipulation may arise when prospective participants are recruited by individuals in a position of authority. The influence of power relationships (e.g., employers and employees, teachers and students, commanding officers and members of the military or correctional officers and prisoners) on the voluntariness of consent should be judged from the perspective of prospective participants, since the individuals being recruited may feel constrained to follow the wishes of those who have some form of control over them. This control may be physical, psychological, financial or professional, for example, and may involve offering some form of inducement or threatening some form of deprivation. In such situations, the control exerted in a power relationship may place undue pressure on the prospective participants. At the extreme, there can be no voluntariness if consent is secured by the order of authorities.

REBs and researchers should also pay particular attention to elements of trust and dependency in relationships (e.g., between physician and patient or between professor and student). These relationships can impose undue influence on the individual in the position of dependence to participate in research projects. Any relationship of dependency, even a nurturing one, may give rise to undue influence even if it is not applied overtly. There may be a greater risk of undue influence in situations of ongoing or significant dependency.

Pre-existing entitlements to care, education and other services should not be prejudiced by the decision of whether to participate in or withdraw from a research project. Accordingly, for example, a physician should ensure that continued clinical care is not linked to research participation. Similarly, where students do not wish to participate in research studies for course credits, they should be offered a comparable alternative.


Coercion is a more extreme form of undue influence, involving a threat of harm or punishment for failure to participate. Coercion would negate the voluntariness of a decision to participate or remain in a research project.


Incentives are anything offered to participants, monetary or otherwise, for participation in research (incentives differ from reimbursements and compensation for injury, which are discussed in Article 3.2[j]). Because incentives are used to encourage participation in a research project, they are an important consideration in assessing voluntariness. Where incentives are offered to participants, they should not be so large or attractive as to encourage reckless disregard of risks. This is a particular consideration in the case of healthy volunteers for the early phases of clinical trials, as discussed in Article 11.2. The offer of incentives in some contexts may be perceived by prospective participants as a way for them to gain favour or improve their situation. This may amount to undue inducement and thus negate the voluntariness of participants’ consent.

This Policy neither recommends nor discourages the use of incentives. The onus is on the researcher to justify to the REB the use of a particular model and the level of incentives. In considering the possibility of undue influence in research involving financial or other incentives, researchers and REBs should be sensitive to issues such as the economic circumstances of those in the pool of prospective participants, the age and decision-making capacity of participants, the customs and practices of the community, and the magnitude and probability of harms (Chapter 4, Section B). Guardians and authorized third parties should not receive incentives for arranging the involvement in research of the individual they represent. However, they may accept reasonable incentives or compensation on behalf of that individual, as long as these are suitable to the circumstances.

(b) To maintain the element of voluntariness, participants shall be free to withdraw their consent to participate in the research at any time, without offering any reason for doing so. In some cases, however, the physical practicalities of the project may prevent the actual withdrawal of the participant partway through, for example, if the project involves only a single intervention, or if the termination of a medical research procedure may compromise the safety of the participant.

The participant should not suffer any disadvantage or reprisal for withdrawing, nor should any payment due prior to the point of withdrawal be withheld. If the research project used a lump-sum incentive for participation, the participant is entitled to the entire amount. If a payment schedule is used, participants shall be paid in proportion to their participation.

(c) The consent process should set out any circumstances that do not allow withdrawal of data or human biological materials once collected. In some research projects, the withdrawal of data or human biological materials may not be possible (e.g., when personal information has been anonymized and added to a data pool). Researchers must provide a rationale to the REB for using collection methods that do not permit subsequent withdrawal of data or human biological materials. Where the terms of the research do not allow for withdrawal of their data or human biological materials, the identity of the participants shall be protected at all times during the project and after its completion. Participants shall also be informed that it is impracticable, if not impossible, to withdraw results once they have been published or otherwise disseminated.

Consent Shall Be Informed

Article 3.2

Researchers shall provide to prospective participants, or authorized third parties, full disclosure of all information necessary for making an informed decision to participate in a research project.


At the commencement of any process of consent, researchers (or their qualified representatives) shall provide prospective participants with the information set out in the following list, as appropriate to the particular research project. Not all the listed elements are required for all research. However, additional information may be required in particular types of research or under particular circumstances.

If a researcher does not include some of the listed disclosure requirements, they should explain to the REB why these requirements do not apply to that particular project. It is also up to the REB to consider whether all elements listed, or additional elements, are necessary to the consent process of the research project.

The information generally required for informed consent includes:

  1. information that the individual is being invited to participate in a research project;
  2. a statement of the research purpose in plain language, the identity of the researcher, the identity of the funder or sponsor, the expected duration and nature of participation, a description of research procedures, and an explanation of the responsibilities of the participant;
  3. a plain language description of all reasonably foreseeable risks and potential benefits, both to the participants and in general, that may arise from research participation;
  4. an assurance that prospective participants:
    • are under no obligation to participate and are free to withdraw at any time without prejudice to pre-existing entitlements;
    • will be given, in a timely manner throughout the course of the research project, information that is relevant to their decision to continue or withdraw from participation; and
    • will be given information on their right to request the withdrawal of data or human biological materials, including any limitations on the feasibility of that withdrawal;
  5. information concerning the possibility of commercialization of research findings, and the presence of any real, potential or perceived conflicts of interest on the part of the researchers, their institutions or the research sponsors;
  6. the measures to be undertaken for dissemination of research results and whether participants will be identified directly or indirectly;
  7. the identity and contact information of a qualified designated representative who can explain scientific or scholarly aspects of the research to participants;
  8. the identity and contact information of the appropriate individual(s) outside the research team whom participants may contact regarding possible ethical issues in the research;
  9. an indication of what information will be collected about participants and for what purposes; an indication of who will have access to information collected about the identity of participants; a description of how confidentiality will be protected (Article 5.2); a description of the anticipated uses of data; and information indicating who may have a duty to disclose information collected, and to whom such disclosures could be made;
  10. information about any payments, including incentives for participants, reimbursement for participation-related expenses and compensation for injury;
  11. a statement to the effect that, by consenting, participants have not waived any rights to legal recourse in the event of research-related harm; and
  12. in clinical trials, information on stopping rules and when researchers may remove participants from trial.

For consent to be informed, prospective participants shall be given adequate time and opportunity to assimilate the information provided, pose any questions they may have, and discuss and consider whether they will participate. The time required for this initial phase of the consent process will depend on such factors as the magnitude and probability of harms, the complexity of the information conveyed, and the setting where the information is given.

The key to informed consent is that prospective participants understand the information being conveyed to them by researchers. Researchers and REBs should consider how best to convey that information to facilitate understanding. For example, written documentation may be supplemented with audio and/or visual aids or accompanied by video presentations.

When language barriers necessitate the assistance of an intermediary for communication between the research team and participants, the researcher should select an intermediary who has the necessary language skills to ensure effective communication (Article 4.1). The involvement of such intermediaries may raise confidentiality issues (Article 5.2).

Paragraphs (a) to (c) require researchers to clearly explain the nature and goals of the research, and other essential information, in a manner that best promotes understanding on the part of prospective participants.

Paragraph (b) requires the disclosure of those who support a particular research project, through funding or sponsorship. It is unethical for researchers to engage in clandestine activities for intelligence, police or military purposes under the guise of research.

Paragraph (c) requires researchers to consider all reasonably foreseeable risks that may result from participation. When research is conducted about an organization or a community, researchers should inform prospective participants within that organization or community of the extent to which the organization or community is collaborating with the research, and of any risk this collaboration may pose to the participant.

Paragraph (d) helps to ensure that a prospective participant’s choice to participate is voluntary. Paragraph (d) also supports the requirement that the consent process continue throughout the research. The consent process should set out any circumstances that do not allow withdrawal of data or human biological materials once collected (Article 3.1[c]).

Paragraph (e) aims at managing real, potential or perceived conflicts of interests. Researchers should separate, to the greatest extent possible, their role as researcher from their other roles as therapists, caregivers, teachers, advisors, consultants, supervisors, employers or the like. If a researcher is acting in dual roles, this fact must always be disclosed to the participant. Conflict of interest matters are further elaborated in Chapter 7.

Paragraph (f) requires that researchers provide a reasonable explanation of the measures they will undertake to publish and otherwise disseminate the results of the research – to the extent that it is feasible, and in a manner that is appropriate. Beyond the ethical obligation to disseminate results in such areas as clinical trials, this requirement is grounded on the reasonable expectation of participants that results will be published or otherwise disseminated in the public domain to advance societal knowledge (addressed further in Articles 11.10 and 4.8). With respect to research involving Indigenous peoples and disclosure of information, see Chapter 9.

Paragraph (h) acknowledges that some institutions may decide to either name an ombudsman for participants or designate a resource person to handle queries, receive complaints and transmit those complaints to the REB. This is a matter for institutions to determine.

Paragraph (i) touches on issues of privacy and confidentiality, secondary use of data, and the possibility of compelled disclosure by the researcher to third parties for administrative and/or legal purposes. These issues are addressed in further detail in Chapter 5 and, in particular, Article 5.2.

Paragraph (j) ensures that participants are informed of the payments they will receive (if any) for their participation. Reimbursement for participation-related expenses is intended to ensure that participants are not put at a direct or indirect financial disadvantage for the time and inconvenience of participation in research. Direct expenses are costs incurred because of research participation (e.g., paying for transportation to, or parking at, the research site), while indirect expenses refer to losses that arise from participation (e.g., taking unpaid leave from work). Participants should also be informed about any compensation they may be entitled to for research-related injuries.

Paragraph (l) is intended to inform the prospective participant in clinical trials of circumstances under which the researcher may end the participant’s involvement in a research project. Clinical trials have stopping rules: statistically significant end points and safety considerations determined in advance that once reached, dictate that the trial must be terminated. As well, researchers may remove participants who are not following the procedures of the clinical trial or for safety reasons (Article 11.6).

Consent Shall Be an Ongoing Process

Article 3.3

Consent shall be maintained throughout the research project. Researchers have an ongoing duty to provide participants with all information relevant to their ongoing consent to participate in the research.


Consent encompasses a process that begins with the initial contact (e.g., recruitment) and carries through to the end of participants’ involvement in the project. Throughout the process, researchers have an ongoing duty to provide participants and REBs with all information relevant to participants’ ongoing consent to participate in the research. The researcher has an ongoing ethical and legal obligation to bring to participants’ attention any changes to the research project that may affect them. These changes may have ethical implications, may be germane to their decision to continue research participation, or may be relevant to the particular circumstances of individual participants. In particular, researchers shall disclose changes to the risks or potential benefits of the research. This gives participants the opportunity to reconsider the basis for their consent in light of the new information.

Rather than an age-based approach to consent, TCPS 2 (2018) advocates an approach based on decision-making capacity as long as it does not conflict with any laws governing research participation. Some children begin participation in a project on the basis of consent from an authorized third party (due to the determination that they lacked capacity to decide on their own behalf) and on the basis of their own assent (Article 3.10). In these cases, if the children mature sufficiently to decide on their own behalf (subject to legal requirements), the researcher must seek the children's autonomous consent in order for their participation to continue. Similarly, in the case of children who are unable to assent to research participation (e.g., infants) at the beginning of a project, the researcher must seek their assent to continue their participation once they are able to understand the purpose of the research as well as its risks and benefits.

Incidental Findings

An “incidental finding” is a discovery about research participants or prospective participants that is made in the course of research, but is outside the objectives of the research study. Incidental findings are considered to be material incidental findings if they are reasonably determined to have significant welfare implications for the participant or prospective participant. Material incidental findings may appear at any stage of the research. For example, material incidental findings can be discovered while screening for eligibility to participate in a study, while collecting baseline information, during study procedure, or during follow-up evaluations.

Article 3.4

Within the limits of consent provided by the participant, researchers shall disclose to the participant any material incidental findings discovered in the course of research.Footnote 2

Determination of materiality

To determine whether an incidental finding is material, expertise relevant to the finding is required. If researchers do not have such expertise, and are unsure of how to interpret the findings or are uncertain whether findings are material, they should seek expertise relevant to the finding and/or refer to professional practices and standards.

Management of foreseeable and non-foreseeable material incidental findings

Incidental findings can arise in any type of research. In some areas of research, such as genetic or genomic research and research that includes imaging, material incidental findings can reasonably be foreseeable in the specific participant population for the study. Where material incidental findings are foreseeable, researchers shall inform participants, as part of the initial consent process, of the likelihood of discovering material incidental findings, and where applicable, should provide information on their strategy to disclose such findings to participants. In addition, researchers should develop a management plan for review by the REB. For genetic research, researchers are required to develop a plan for managing information that may be revealed through their research, and submit the plan for REB review (Article 13.2).

In other areas of research, material incidental findings may not be reasonably foreseeable, but can be discovered unexpectedly in the course of the research. Upon discovery of an incidental finding, the researcher shall determine whether the finding is material, and report the discovery to the REB in accordance with guidance in Article 6.15. The researcher should describe the process used to determine the materiality of the finding(s), and present a plan for disclosing such findings to the participants.

Regardless of whether the material incidental findings were foreseeable, REBs should assess the researcher’s plan to disclose material incidental findings to participants. If there is uncertainty as to whether a research project requires such a plan, researchers and REBs can make this determination on a case-by-case basis. The final decision on the need for a plan rests with the REB.

Consent and departures from consent

Upon discovery of a material incidental finding, the principle of Concern for Welfare places an obligation on researchers to share it with the relevant participants. To respect the participants’ autonomy, the communication of the findings determined to be material can only be done when participants or their authorized third parties have consented to receiving them initially or as part of the ongoing consent process. See Articles 3.1, 3.2 and 3.3 for the consent process and Article 13.3 for human genetic research).

Where the researchers have undertaken, in the course of the consent process, not to disclose material incidental findings, and researchers discover an unforeseeable material incidental finding that can be addressed with a potentially significantly beneficial intervention, researchers should consult their REBs to determine whether there is a sufficient ethical basis to disclose the finding to the participant, and if so, how to disclose it.

There may be limitations to the consent to receiving material incidental findings. For example, in the case of children, authorized third parties, who, by law, must always exercise their authority in the best interest of the child, must receive any findings for the child that are actionable immediately or during childhood.

Researchers should exercise care and sensitivity in determining who discloses material incidental findings that may have a negative impact on the welfare of participants, and how that disclosure is made. Researchers should assist participants in understanding the material incidental finding(s). Researchers’ assistance may include suggesting that participants consider seeking additional advice from people they trust, such as family members, friends, experts or professionals. When necessary, researchers should direct participants to a qualified professional to discuss the possible implications of material incidental findings for their welfare.

In some cases, incidental findings may trigger legal reporting obligations. Researchers should be aware of these obligations and, as part of the initial consent process, should inform participants of the limits to confidentiality (Article 5.1).

Exceptions to the obligation to disclose

Researchers may also request an exception to their obligation to disclose material incidental findings, based on the impracticability or impossibility of disclosing such findings to the participant. “Impracticable” refers to undue hardship or onerousness that jeopardizes the conduct of the research; it does not mean mere inconvenience. Disclosure may be impossible or impracticable when participants or their authorized party may be deceased or difficult to track due to insufficient identifiers, cost, or time elapsed. The onus is on the researcher to justify to the REB the need for the exception.

Consent Shall Precede Collection of, or Access to, Research Data

Article 3.5

Research shall begin only after the participants, or their authorized third parties, have provided their consent.


In keeping with the principle of Respect for Persons, participants shall provide their consent prior to engaging in research. This is the clearest demonstration that their participation is based on consideration of the risks and potential benefits of the research project, and other principles in this Policy.

There are exceptions to this general ethical requirement, however, set out in Articles 3.7A and 3.8.

This article does not apply to conversations that researchers may have with prospective participants as part of the development of the design of their research. These preliminary conversations – which may include negotiations concerning the terms on which a researcher may engage with a particular community or group – do not in themselves constitute research and therefore do not require consent (Chapter 2, Article 6.11, Articles 9.3 to 9.6 and Article 10.1).

Critical Inquiry

Article 3.6

In critical inquiry, permission is not required from an institution, organization or other group in order to conduct research on them. If a researcher engages the participation of members of any such group without the group’s permission, the researcher shall inform participants of any foreseeable risk that may be posed by their participation.


Research in the form of critical inquiry, that is, the analysis of social structures or activities, public policies or other social phenomena, requires an adjustment in the assessment of consent. Where the goal of the research is to adopt a critical perspective with respect to an institution, organization or other group, the fact that the institution, organization or group under study may not endorse the research project should not be a bar to the research receiving ethics approval. Where social sciences or humanities researchers seek knowledge that critiques or challenges the policies and practices of institutions, governments, interest groups or corporations, researchers do not need to seek the organization’s permission to proceed with the proposed research. If institutional approval were required, it is unlikely that research could be conducted effectively on such matters as institutional sexual abuse or a government’s silencing of dissident scientists. Important knowledge and insights from research would be forgone. Specific requirements pertain to First Nations, Inuit and/or Métis organizations, which are discussed in detail in Articles 9.4 to 9.8.

Researchers and REBs should be aware that institutions, organizations or other groups under study may have requirements for allowing access to their sites and to participants, and that some of these may have established mechanisms or guidelines, for instance, school boards, Indigenous communities (Chapter 9), correctional services, and community groups. Refer to Article 8.3 for more information. Nevertheless, REBs should not prohibit research simply because the research is unpopular or looked upon with disfavour by a community or organization, in Canada or abroad. Similarly, REBs should not veto research on the grounds that the government in place or its agents have not given approval for the research project or have expressed a dislike for the researchers.

However, individuals who are approached to participate in a research project about their organization should be fully informed about the views of the organization regarding the research, if these are known. Researchers shall inform participants when the permission of the organization has not been obtained. Researchers engaging in critical inquiry need to be attentive to risks of both stigmatization and breach of privacy, to those who participate in research about their organization. In particular, prospective participants should be fully informed of the possible consequences of participation.

REBs should, however, legitimately concern themselves with the welfare of participants and the security of research materials in such circumstances. When participants are vulnerable to risks from third parties (e.g., authoritarian regimes, gang leaders, employers) on account of their involvement in research, researchers should ensure that copies of field materials are kept in secure locations. When sharing research materials such as consent forms or transcripts of field notes with participants, researchers must honour their commitment to protect the anonymity and confidentiality of participants to ensure that their human rights, and the ethical principles set out in this Policy, are not compromised. In general, regardless of where the researchers conduct their research, researchers and REBs should concern themselves with safeguarding information while it is in transit (Articles 5.1 to 5.4).

REBs should also be aware that some research, for instance, research involving critical assessments of public, political or corporate institutions and associated public figures, may be legitimately critical and/or opposed to the welfare of those individuals in a position of power, and may cause them some harm. There may be a compelling public interest in this research. Therefore, it should not be blocked through the use of risk-benefit analysis. Such research should be carried out according to the professional standards of the relevant discipline(s) or field(s) of research. Where an individual in a position of power is invited to be interviewed or gives access to private papers and thus becomes a participant as defined by this Policy, Article 3.2 applies. See also Articles 3.12, 9.7 and 10.2). In such cases, the balance of risks to those who are the object of the research is mainly considered along with the potential benefit of new knowledge to society and the indirect benefits to the population affected by the public, political or corporate institutions to which the participant belongs.

B. Departures from General Principles of Consent

Articles 3.1 to 3.5 set out the default requirements for seeking the consent of individuals to participate in research. However, there are some research questions that cannot be answered without an alteration to these consent requirements. For example, the question of what factors influence whether people will choose to return a wallet dropped by someone on the street could not be answered if the prospective participants were alerted to the presence of the researcher observing them and to the presence of the confederate dropping the wallet in front of them. Alterations to consent requirements may include providing prospective participants with only partial disclosure about the purpose of the study, deceiving prospective participants entirely about the purpose of the study, and not informing participants that they (or their data or biological materials) are involved in a study.

Article 3.7A sets out the conditions which a researcher must satisfy in order for an REB to approve research involving any alteration to consent requirements. The lack of prior consent, or of fully informed consent, may be addressed through debriefing conducted as soon as possible following participants’ involvement in the research, and within a timeframe that allows participants to withdraw their data or human biological materials (where possible, practicable [see Glossary] and appropriate). Article 3.7B provides guidance with respect to debriefing in the context of an alteration to consent requirements.

Alterations to Consent Requirements

Article 3.7A

The REB may approve research that involves an alteration to the requirements for consent set out in Articles 3.1 to 3.5 if the REB is satisfied, and documents, that all of the following apply:

  1. the research involves no more than minimal risk to the participants;
  2. the alteration to consent requirements is unlikely to adversely affect the welfare of participants;
  3. it is impossible or impracticable (see Glossary) to carry out the research and to address the research question properly, given the research design, if the prior consent of participants is required;
  4. in the case of a proposed alteration, the precise nature and extent of any proposed alteration is defined; and
  5. the plan to provide a debriefing (if any) that may also offer participants the possibility of refusing consent and/or withdrawing data and/or human biological materials, shall be in accordance with Article 3.7B.

In the circumstances described under Article 3.7A, the nature of the research may justify some alteration(s) to consent requirements if the potential benefits outweigh the foreseeable risks. As stated in paragraphs (a) and (b), the risks to participants must fall within the definition of no more than minimal risk (Chapter 2, Section B), and the alteration to the requirements must be unlikely to adversely affect participants’ welfare. The potential benefits to be considered include benefits to the participants themselves, to the group they represent and/or to society more generally. Note that in paragraph (c), “impracticable” refers to undue hardship or onerousness that jeopardizes the conduct of the research. It does not refer to mere inconvenience (see Glossary). Researchers must clearly describe the nature and extent of the proposed alteration(s) (paragraph [d]) and their plans with respect to debriefing participants, in accordance with paragraph (e). It is the responsibility of researchers to justify the need for any alteration to consent requirements to the satisfaction of their REBs.

Alterations to consent should be permitted only to the extent necessary. If the aims of the research can be achieved with a design that allows for full – or fuller – prior disclosure (in accordance with Articles 3.1 to 3.5), then that design must be adopted. It is the responsibility of REBs, however, to understand that certain research methods necessitate a different approach to consent, and to exercise judgment on whether the need for the research justifies any alterations to consent requirements. In determining whether to allow any alterations to consent requirements, REBs must consider both the proposed alterations and the proposed plan for debriefing or justification for not debriefing. In other words, the guidance in Articles 3.7A and 3.7B must be considered together in determining whether an alteration to consent requirements is ethically acceptable.

It should be noted that, in some cases of randomization and blinding in clinical trials, neither the participants nor the researchers know which treatment the participant will be receiving. As long as participants are informed of the probability of their assignment to each arm of the trial, this random and blind assignment does not constitute an alteration to consent requirements.

Research involving partial disclosure or deception

Some social science research, particularly in psychology, seeks to learn about human responses to situations that have been created experimentally. Some types of research can be carried out only if the participants do not know the true purpose of the research in advance. For example, some social science research that critically probes the inner workings of publicly accountable institutions might never be conducted without the limited use of partial disclosure. In some research that uses partial disclosure or deception, participants may be asked to perform a task and informed about only one of several elements the researchers are observing. Research employing deception can involve a number of techniques, such as giving participants false information about themselves, events, social conditions and/or the purpose of the research. For such techniques to fall within the exception to the general requirement of full disclosure for consent, the research must meet all the requirements of Article 3.7A.

Exception to the requirement to seek prior consent

In the circumstances described under Article 3.7A, an REB may allow an exception to the requirement that researchers seek consent from participants prior to collection of data and/or human biological materials. Researchers must demonstrate that this alteration to consent requirements is necessary to address the research question and that the lack of prior consent will not have an adverse impact on the welfare of participants. They must also demonstrate that the benefits of the research, whether direct, indirect or societal, justify any risks associated with no prior consent. For example, a study of the effect of environmental toxins on the members of nearby communities may involve the analysis of the level of toxins present in discarded hair clippings from the barber shops of these communities. The researchers may make the case that the collection and analysis of the hair clippings pose no risks to participants, that seeking prior consent for the use of the hair clippings could lead to a general panic about environmental toxins among the members of these communities, and that the possible benefits of identifying environmental toxins so that they can be removed justify this approach to the research question.

REBs must consider whether it is in the participants’ best interests to be informed of the research (and to what extent) if not before, then afterwards (Article 3.7B). If the research design calls for no prior consent and no debriefing, then the participants may never know of their involvement. This raises ethical issues that differ somewhat from other alterations to consent requirements as these participants will have no opportunity to ask questions about the nature and purpose of the study or to request the withdrawal of their data and/or human biological materials (where possible, practicable [see Glossary] and appropriate). In light of these issues, the REB should apply greater scrutiny (Article 2.9) to the justification for an exception to the requirement to seek prior consent and an exception to the requirement to debrief (Article 3.7B).

Note that Article 3.7A does not address the exception to the requirement to seek consent for secondary use of identifiable information; this topic is addressed in Article 5.5A.

Participants’ vulnerability

In considering the need for an alteration to consent requirements, researchers and REBs should also consider whether the prospective participants (as individuals, groups or populations) are in circumstances that may make them vulnerable in the context of research (Article 4.7). The existence of such circumstances may require greater effort to minimize risks to participants and/or maximize potential benefits (Chapter 2, Section B).

Population and public health research

Due to the nature of the research question and the need to test interventions that operate at the population level, some population and public health studies cannot be done with prior informed consent. For example, a cluster-randomized trial comparing two different stop smoking campaigns in two or more communities would not be able to answer the research question if community members were alerted, through a consent process, to the presence of the campaign and the existence of other campaigns in different communities, as this knowledge could affect the group response to the campaigns. Similarly, in a study comparing different types of water treatment facilities, it would not be possible to obtain individual informed consent for the type of water treatment each individual in a community is to receive. Researchers should, however, seek community engagement prior to data collection (Chapter 9).

It is up to researchers to adequately explain why their research question cannot be answered without an exception to the requirement to seek prior consent. REBs are advised to have population and public health expertise involved in reviews of this type of research (Articles 6.4 and 6.5).

Community-level interventions controlled by researchers that have been approved to proceed without consent or a community engagement process may inadvertently expose people who do not meet the study’s inclusion criteria to the intervention. Researchers and REBs should assess whether there are any risks to individuals posed by this exposure, and if so, consider ways to narrow the exposure. For example, the use of observational methods, census data or a source informed about the community could help researchers identify community members who should be excluded (e.g., do not knock on their doors; do not send flyers to that address). In the case of interventions that cannot help but be visible to, or affect the entire community (e.g., billboard ads, radio broadcasts), there would be no way to exclude non-target population community members or visitors to the community. Accordingly, the REB should be satisfied that any risks of inadvertent exposure to the intervention are minimal.

Debriefing in the Context of Alterations to Consent Requirements

Article 3.7B

  1. Debriefing must be a part of all research involving an alteration to consent requirements (Article 3.7A) whenever it is possible, practicable and appropriate.
  2. Participants in such research must have the opportunity to refuse consent and request the withdrawal of their data and/or human biological materials whenever possible, practicable and appropriate (Article 3.1).

Where alterations to consent have been used, debriefing is important in maintaining the participant’s trust in the research community. Often, debriefing in this context can be a simple and straightforward candid disclosure as described in Article 3.2. To allow for the possibility that participants may wish to withdraw their data or biological materials once they know the details of the study (see Post-Debriefing option to withdraw data and/or human biological materials in this Application), debriefing should take place while it is still possible to give participants this option (e.g., prior to merging or de-identification).

Researchers must explain why participants were temporarily led to believe that the research, or some aspect of it, had a different purpose, or why participants received less than full disclosure. In cases where participants were not asked for their consent prior to collection of data and/or human biological materials, researchers must explain why this exception to consent requirements was necessary. Researchers must give details about the importance of the research and the necessity of having to use alterations to consent requirements, and address any concerns raised by participants. In order to address any misconceptions that may have arisen, researchers must explain why these research procedures were necessary to obtain scientifically valid findings. When debriefing, researchers should be alert and sensitive to participants’ needs, feelings, reactions and concerns. REBs should assess the risks and benefits of the debriefing itself and whether the proposed plan is appropriate for participants – particularly those whose circumstances may make them vulnerable in the context of research and/or who lack the capacity to make a consent decision.

When it is not appropriate to provide complete details of the research in a debriefing, the level of detail should be determined by considering the impact of the information on the participant in terms of foreseeable risks and potential benefits. It should also be proportionate to the sensitivity of the issue and tailored to the decision-making capacity of participants. For example, in research involving children who do not have the capacity to make a consent decision on their own behalf, it may be more appropriate to debrief the parents, guardians or authorized third parties as well as the participants themselves. The debriefing process should be based upon the participants’ capacity to understand the information provided. Note that in some cases, excluding children from a debriefing may be justified (e.g., when debriefing is focused on findings of a sensitive nature that relate to the child, such as intellectual capacity). In other cases, it may be more appropriate to debrief the entire family or community. Immediate, full debriefing of all individuals who have contributed data may not be possible or practicable in all cases. In studies with data collection over a longer term, debriefing may have to be deferred until the end of the project.

Post-Debriefing option to withdraw data and/or human biological materials

At the time of debriefing, participants should, whenever possible, practicable and appropriate, be able to indicate their consent/assent or their refusal for the continued use of their data or human biological materials. In cases where participants express concerns about their participation in a project, the researcher must address their concerns (e.g., by explaining the rationale for the research design, answering questions about data usage or privacy). Regardless of whether any concerns are raised, the researcher must give participants the option of removing their data and/or human biological materials unless this option is impossible, impracticable (see Glossary) or inappropriate.

In determining whether it is ethically acceptable not to permit the withdrawal of data and/or human biological materials, REBs must consider whether withdrawal of data is possible or practicable. If researchers intend to collect data or human biological materials without identifying information, or if all identifying information will be removed, it may not be possible for researchers to withdraw the data associated with specific individuals. Researchers must provide a rationale for using collection methods that do not permit subsequent withdrawal of data or human biological materials. REBs must also consider whether the option to withdraw data is appropriate. In some types of research, permitting the withdrawal of data and/or human biological materials could skew the results of the research, invalidating the study and denying potential benefits to society. The invalidation of study findings may also demonstrate a lack of respect for the contributions made by other participants. The onus is on researchers, however, to satisfy the REB that the withdrawal of data or biological materials by individual participants would threaten the validity of their research.

Where the terms of the research proposal do not permit the participants to withdraw their data, in the absence of the participants’ consent, the identity of the participants shall be protected at all times during the project. Participants who express concern about the conduct of the project at the time of debriefing, or who contest the limits imposed on withdrawing their data, should be given the contact information for the REB that approved the research. Researchers must report to the REB concerns about the conduct of the project raised by participants at the time of debriefing.

Exception to the requirement to debrief

There may be circumstances in which debriefing is impossible, impracticable or inappropriate in research involving alterations to consent requirements. Note that “impracticable” refers to undue hardship or onerousness that jeopardizes the conduct of the research. It does not refer to mere inconvenience. The onus is on researchers to satisfy the REB that their research involves circumstances that make it impossible, impracticable or inappropriate to offer debriefing.

When considering whether to grant an exception to the requirement to debrief, REBs should consider the level of potential harm to the participant which the debriefing itself may cause and the impact of the debriefing on the feasibility of the research. When seeking an exception to the requirement to debrief, researchers must also provide a plan to disseminate information about the study to participants and/or their communities (e.g., through local media, direct mail). This plan is of particular importance when the findings may affect participant welfare.

Consent for Research in Individual Medical Emergencies

This section addresses the exception to consent in situations where an individual who requires urgent medical care is unable to provide consent for research due to loss of consciousness or decision-making capacity – and the delay to seek authorized third party consent could seriously compromise that individual’s health. Certain types of medical emergency practices can be evaluated only when they occur, hence the need for this exception.

This section is to be distinguished, however, from situations where there is a publicly declared emergency (such as the SARS crisis or a major flood) that disrupts the ordinary system for obtaining REB approval for research. For guidance on research ethics review during a publicly declared emergency, see Articles 6.21 and 6.22.

Article 3.8

Subject to all applicable legal and regulatory requirements, research involving medical emergencies shall be conducted only if it addresses the emergency needs of the individuals involved, and then only in accordance with criteria established in advance of such research by the REB. The REB may allow research that involves medical emergencies to be carried out without the consent of participants, or of their authorized third party, if all of the following apply:

  1. A serious threat to the prospective participant requires immediate intervention.
  2. Either no standard efficacious care exists, or the research offers a realistic possibility of direct benefit to the participant in comparison with standard care.
  3. Either the risk is not greater than that involved in standard efficacious care, or it is clearly justified by the prospect for direct benefits to the participant.
  4. The prospective participant is unconscious or lacks capacity to understand the risks, methods and purposes of the research project.
  5. Third party authorization cannot be secured in sufficient time, despite diligent and documented efforts to do so.
  6. No relevant prior directive by the participant is known to exist.

When a previously incapacitated participant regains decision-making capacity, or when an authorized third party is found, consent shall be sought for continuation in the project, and for subsequent examinations or tests related to the research project.


For purposes of studying potential improvement in the treatment of life-threatening conditions, Article 3.8 outlines an exception (in addition to that in Article 3.7A) to the general obligation of seeking consent from those participating in research.

It is the responsibility of researchers to justify to the REB the need for this exception. The underlying assumption of Article 3.8 is that participants could not receive any direct benefits of the research without setting aside the need for the researcher to seek the prior consent of participants, or of their authorized third party. Article 3.8 indicates that research in emergency medicine must be reviewed by the REB, be restricted to the emergency needs of the participants, and be conducted under criteria designated by the REB.

It is unethical to expose participants to any additional risk without their consent if standard efficacious care exists, unless it can clearly be shown that there is a realistic possibility of meaningful improvement of the participant’s condition. Accordingly, paragraphs (b) and (c) of Article 3.8 indicate that researchers and REBs must assess the risks and potential benefits of proposed research against existing standard efficacious care.

To respect the autonomy of the participant, Article 3.8(e) requires researchers to undertake diligent efforts to contact authorized third parties, if practicable, and to document such efforts for the benefit of both the participant and the continuing ethics review functions of the REB. The article also requires that participants who regain decision-making capacity be promptly afforded the opportunity to consent to their continued participation. Concern for the patient’s welfare is paramount and should be informed by ethical and professional judgment.

Because their incapacity to make decisions puts them in circumstances that may make them vulnerable in the context of research, prospective participants for emergency research are owed special ethical obligations and protection commensurate with the risks involved. Their welfare should be protected by additional safeguards, where feasible and appropriate. These might include additional scientific, medical or REB consultation; procedures to identify prospective participants in advance so that consent may be sought prior to the occurrence of the emergency situation; consultation with former and prospective participants; and special monitoring procedures to be followed by data safety and monitoring boards.

C. Decision-Making Capacity

Decision-making capacity refers to the ability of prospective or actual participants to understand relevant information presented about a research project and to appreciate the potential consequences of their decision to participate or not participate. This ability may vary according to the complexity of the choice being made, the circumstances surrounding the decision, or the point in time at which consent is sought. The determination of capacity to decide whether to participate in research, then, is not a static determination. It is a process that may change over time, depending on the nature of the decision the prospective participant needs to make, and on any changes in the participant’s condition. Assessing decision-making capacity is a question of determining, at a particular point in time, whether a participant (or prospective participant) sufficiently understands the nature of a particular research project, and the risks, consequences and potential benefits associated with it.

One may therefore have diminished capacity in some respects but still be able to decide whether to participate in certain types of research. Researchers should be aware of all applicable legal and regulatory requirements with respect to decision-making capacity and/or consent. 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.

In keeping with the principle of Justice, those who lack the capacity to decide on their own behalf must neither be unfairly excluded from the potential benefits of research participation, nor may their lack of decision-making capacity be used to inappropriately include them in research. REBs and researchers should be aware of these ethical considerations and seek to find a balance between them for the benefit of prospective participants who lack decision-making capacity (Chapter 4).

As indicated in Chapter 1, Respect for Persons and Concern for Welfare entails special ethical obligations to individuals whose circumstances may make them vulnerable in the context of research. Such obligations often translate into special procedures to promote and protect their interests. This may include the development of consent materials that are appropriate to the cognitive and communication abilities of prospective participants. Articles 3.9, 3.10 and 3.11 describe special procedures for research involving individuals who lack decision-making capacity.

Article 3.9

For research involving individuals who lack the capacity, either permanently or temporarily, to decide for themselves whether to participate, the REB shall ensure that, as a minimum, the following conditions are met:

  1. The researcher involves participants who lack the capacity to decide on their own behalf to the greatest extent possible in the decision-making process.
  2. The researcher seeks and maintains consent from authorized third parties in accordance with the best interests of the persons concerned.
  3. The authorized third party is not the researcher or any other member of the research team.
  4. The researcher demonstrates that the research is being carried out for the participant’s direct benefit, or for the benefit of other persons in the same category. If the research does not have the potential for direct benefit to the participant but only for the benefit of the other persons in the same category, the researcher shall demonstrate that the research will expose the participant to only a minimal risk and minimal burden, and demonstrate how the participant’s welfare will be protected throughout the participation in research.
  5. When authorization for participation was granted by an authorized third party, and a participant acquires or regains decision-making capacity during the course of the research, the researcher shall promptly seek the participant’s consent as a condition of continuing participation.

The decision of authorized third parties should be based on their knowledge of the prospective participants and on consideration of the prospective participants’ welfare. The third parties should not be in a position of conflict of interest when making their decision.

Article 3.9 outlines other safeguards to protect those who lack the capacity to consent to participate in research. The article details several considerations relevant to the use of third party authorization. Beyond the legal and regulatory requirements for seeking consent from authorized third parties, family members and friends may also provide information to the authorized third party about the interests and previous wishes of prospective participants. An authorized third party should take into account any research directives given in accordance with Article 3.11.

Article 3.10

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. Prospective participants’ dissent will preclude their participation.


Many individuals who lack legal capacity to make decisions may still be able to express their wishes in a meaningful way, even if such expression may not fulfill all 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 decision-making 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 decision-making capacity is diminishing or fluctuating; and
  3. those whose decision-making capacity remains only partially developed, such as those living with permanent cognitive impairment.

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.

Research Directives

Although advance directives for treatment are recognized as a legitimate tool in health care, the use of directives in the context of research is not well developed, and they have no legal status. For the purposes of this Policy, research directives should be understood to express an individual’s preferences for participation in future research in the event that the individual loses capacity. Research directives are written instructions to be used by the authorized third party as information about a prospective participant’s preferences when the third party is asked to provide substitute consent.

The efficacy of research directives is unknown, and their legal status has not yet been recognized or tested. Research directives, nevertheless, are congruent with this Policy’s core principle of Respect for Persons. The use of research directives respects the right of individuals to express their preference regarding participation in research and respects privacy by allowing individuals to control information about themselves and materials from their bodies. Authorized third parties should consult with an individual’s research directive when deciding whether to consent to participation in research on behalf of that individual.

Article 3.11

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.


Research directives allow individuals with decision-making capacity to express preferences about their future participation in research should they ever lose this capacity. Researchers and authorized third parties should take these directives into account during the consent process, but only if the individual who provided the research directive lacks decision-making capacity at the time the research is initiated. Research directives may also be used for participants who have decision-making capacity when research is initiated but lose this capacity during research.

Research directives are useful to individuals who are already participating in research as well as those who are not participating but may wish to participate in research at a later date. They give individuals a range of options regarding future participation in research. The use of research directives is particularly relevant for research involving participants with diminishing and/or fluctuating decision-making capacity or degenerative conditions, and research that collects information or human biological materials.

The use of research directives does not alter the requirements for consent as articulated by the provisions of this Policy. In particular, in accordance with Article 3.9, researchers are required to seek the consent of authorized third parties before individuals who lack decision-making capacity can participate in research. If an individual regains this capacity, the researcher should promptly seek the consent of the individual as a condition of continuing participation.

Researchers, institutions and organizations may suggest the use of research directives in order to give participants an opportunity to express preferences about the use of information or human biological material that has already been collected. Researchers who collect information or human biological materials for a specific research project may anticipate subsequent research uses. Some types of research initiatives (e.g., the creation of large databases sometimes known as “research platforms”) involve long-term retention and use of information or human biological materials for research purposes (e.g., longitudinal studies that involve biobanking). When data for these platforms are initially collected, it is not typically possible to specify every research study that could be carried out using the participants’ information or human biological materials. Research directives may be used in these contexts to give participants the opportunity to express their preferences about future research should they lose decision-making capacity (Article 5.5A[d] for expression of preferences in the context of secondary use of data).

In long-term projects, research directives may be used to allow participants to make choices about other aspects of research participation. For example, participants could specify preferences about receiving findings, or allowing the continued use of their information or samples in the event that they lose decision-making capacity, or after they die.

Individuals can also use research directives to express preferences concerning participation in future research. For example, individuals in an early stage of cognitive impairment may use a research directive to express their preferences for future participation in research that, due to diminishing decision-making capacity, they would not otherwise be able to consent to on their own. Research directives also allow existing participants to express their preference to continue to participate in research should they lose decision-making capacity. Research directives should be as specific as possible, and in the event of ambiguity or imprecision, should be interpreted narrowly. Individuals should be encouraged to periodically update their research directives and, if possible, construct directives in contemplation of specific types of research interventions. Research directives should be written, dated and witnessed, and include a declaration about the decision-making capacity of the individual at the time the directive was made.

D. Consent Shall Be Documented

Article 3.12

Evidence of consent shall be contained either in a signed consent form or in documentation by the researcher of another appropriate means of consent.


Written consent in a signed statement from the participant is a common means of demonstrating consent, and in some instances, is mandatory (e.g., Health Canada regulations under the Food and Drugs Act, the Civil Code of Québec). However, there are other means of providing consent that are equally ethically acceptable. In some types of research, and for some groups or individuals, written signed consent may be perceived as an attempt to legalize or formalize the consent process and therefore may be interpreted by the participant as a lack of trust on the part of the researcher. In these cases, oral consent, a verbal agreement or a handshake may be required, rather than signing a consent form. In some cultures, the exchange of gifts symbolizes the establishment of a relationship comparable to consent.

Where consent is not documented in a signed consent form, researchers may use a range of consent procedures, including oral consent, field notes and other strategies, for documenting the consent process. Consent may also be demonstrated solely by the actions of the participant (e.g., through the return of a completed questionnaire). Where there are valid reasons for not recording consent in writing, the procedures used to seek consent must be documented (Article 10.2).

Whether or not a consent form is signed, it may be advisable to leave a written statement of the information conveyed in the consent process with the participant. For participants, it is evidence that they have agreed to participate in a particular research project. It may serve as a reminder to participants of the terms of the research project. It may also facilitate the ability of participants to consider and reconsider their involvement as the research proceeds. However, researchers should not leave any documentation with participants if it may compromise their safety or confidentiality. Additionally, in some cases it may not be appropriate to leave a written statement, such as in cultural settings where such written documentation is contrary to prevailing norms.


Centre of Genomics and Policy (CGP), Maternal Infant Child and Youth Research Network (MICYRN), Best Practices for Health Research Involving Children and Adolescents [ PDF (1.16 MB) - external link ], 2012. Retrieved on June 29, 2018.

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