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Overview
Chapter 4.5 of the National Statement addresses research involving people experiencing physical or mental ill-health or disability; this is the chapter's full title in the 2025 edition, reflecting a consolidation of what were two separate chapters in the 2023 National Statement, covering people highly dependent on medical care and people with cognitive impairment, intellectual disability, or mental illness. Ill-health and disability are treated as conditions on a gradient of severity that can be permanent, chronic, episodic, or temporary, and that fluctuate in both severity and expression. The central principle is inclusion: ill-health, disability, or age should not be a barrier to participating in research, and many people with chronic illness or disability value the opportunity and have the right to participate.
As with the rest of Section 4, the 2025 edition removed the automatic requirement for full HREC review for this population. Some research involving people with ill-health or disability is lower risk and should not automatically be treated as requiring HREC review; the appropriate pathway is determined case by case (NS 4.5.9, 4.5.36).
From protection to presumption of capacity
The chapter names a historical problem directly: the design, review, and conduct of research have, in the past, disempowered or excluded people experiencing ill-health or disability because of assumptions about their ability to decide or consent, often based on a diagnostic label rather than an assessment of the individual. The 2025 edition responds with an explicit presumption: adults should be assumed able to consent for themselves unless an assessment of their individual ability, or the context of the research, indicates otherwise. Inclusion and self-determination should be paramount in decisions about research involving this population (NS 4.5.2).
Researchers must indicate how they will determine the impact of a participant's ill-health or disability on their decision-making capacity, their capacity to provide valid consent, and their ability to participate (NS 4.5.3), including who will decide, what criteria will be used, and how capacity will be reviewed as the research proceeds (NS 4.5.4).
Fluctuating capacity and advance directives
Where capacity to consent may fluctuate or be lost during the research, this possibility should be discussed with the participant in advance, and their wishes about what should happen should generally be followed (NS 4.5.5). Advance directives can record a participant's views about their participation for use if capacity later declines; these may be project-specific or apply more broadly to related or future research, in the same way as the scope of consent described in NS 2.2 (NS 4.5.6). Advance directives cannot be used where jurisdictional legislation prohibits them, and given the legal complexity involved, applicants proposing to rely on one should obtain independent legal advice.
Delayed, deferred, or retrospective consent is not ethically permissible (NS 4.5.7). Signs of reluctance, discomfort, or distress must not be assumed to mean a definitive wish to end participation: researchers should pause the activity, explore the cause, and where possible use strategies to calm or reorient the participant, but a sustained and unequivocal refusal must be respected and treated as a binding withdrawal of consent (NS 4.5.8). If a participant later regains capacity, researchers must explain what continuing involves, seek their agreement to continue, and respect a decision to stop (NS 4.5.24, NS 4.5.34).
Accessible participation
Exclusion of people with disability from research is unethical unless adequately justified; researchers who explicitly exclude people with disability must disclose this to reviewers and disclose it in any published research outputs (NS 4.5.27). Researchers should design projects so that people with disability can participate, including by adapting the timing and process of consent to the participant's disability, and by using data collection methods, spaces, and schedules that are accessible and accommodate needs such as rest breaks (NS 4.5.28). This can include home-based assessment before recruitment, varied consent materials such as short videos, illustrations, or Easy Read text, adapted procedures, and providing or arranging transport to the research site (NS 4.5.33). Planning should involve consultation with potential participants, disability representative organisations, carers or family members, both in designing the project and in developing information materials (NS 4.5.29, NS 4.5.30). See Accessible consultation for practical guidance on designing this engagement, and Plain language, Easy English and Easy Read for accessible communication formats.
For people who are seriously ill or unconscious, the same principle of inclusiveness applies, subject to additional safeguards; research may proceed where it is likely to improve care for the population, relevant legislation is satisfied, and either valid consent has been obtained from the participant or an authorised person, or the participant has capacity and finds the risks acceptable (NS 4.5.13). For emergency or intensive care research, the National Statement sets a hierarchy: obtain consent from the participant; if not possible, from a guardian or authorised person; if neither is feasible, consider a waiver of consent; and only if waiver requirements cannot be met, seek HREC approval to proceed without consent under the strict conditions in NS 4.5.22. Research involving terminally ill participants should not routinely exclude them, should ensure benefits justify risks without exaggerating prospects of benefit, and should give priority to participants' wishes to spend time as they choose, particularly with family (NS 4.5.25, 4.5.26).
Application in evaluation, social research and market research
Most evaluation, social research, and market research involving people with disability or ill-health will not touch upon the emergency care or terminal illness provisions. The more common questions are about accessible consent materials, adapted interview formats, and whether program or service evaluations have unjustifiably excluded people with disability from the sample. A service evaluation that only recruits participants able to complete a written online survey, for example, should consider whether this excludes people who would benefit from alternative formats, and if exclusion is proposed, should disclose and justify it (NS 4.5.27). Market research recruiting people with disability should apply the same presumption of capacity and offer accessible materials rather than treating disability status as a basis for exclusion.
What reviewers look for
- A stated method for assessing capacity, applied to the individual rather than inferred from diagnosis or group membership (NS 4.5.3, NS 4.5.4)
- Evidence of consultation with people with disability, representative organisations, and/or supporting individuals during planning (NS 4.5.29, NS 4.5.30)
- Accessible information, consent, and data collection formats matched to participants' needs (NS 4.5.28, NS 4.5.33)
- A protocol for managing reluctance, discomfort, or distress that does not treat it as an automatic withdrawal (NS 4.5.8)
- Where exclusion of people with disability is proposed, a clear justification and a plan to disclose it in outputs (NS 4.5.27)
- For emergency, intensive care, or terminally ill cohorts, evidence that the consent hierarchy in NS 4.5.17 to 4.5.26 has been followed
Related resources
See Accessible consultation and Plain language, Easy English and Easy Read for practical guidance on inclusive design and communication, When consent can be modified for related consent-adjustment mechanisms, and Assessing risk and benefit (NS 2.1) for the risk framework that determines review pathway.
This page was last updated on 16 September 2026.
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This article makes reference to the National Statement on Ethical Conduct in Human Research 2025. It is intended as practical guidance and does not constitute legal advice.
AI Disclosure: Resources in this library were prepared using Large Language Models with input from Iris Ethics staff who guided the scope and design. Subsequent revisions and final versions were developed and approved by Iris Ethics staff.