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Overview
Participant selection criteria (who is eligible to participate and who is excluded) must be clearly described and justified in ethics applications. The National Statement requires that the selection, exclusion, and inclusion of participants be fair and accurately described (NS 1.4), and that the inclusion/exclusion criteria for a project be justifiable and align with the objectives and theoretical basis of the research/evaluation (NS 3.1.13–3.1.14).
Inclusion criteria
Inclusion criteria define who is eligible to participate and should be derived directly from the research/evaluation questions and the theoretical basis of the project (NS 3.1.13). Criteria must not exclude potential participants for reasons unrelated to the research/evaluation unless there is a specific ethical or methodological justification. The principle of justice requires that groups are not denied the opportunity to benefit from, or contribute to, research or evaluation without good reason (NS 1.4(f)).
Exclusion criteria
Exclusion criteria must be justifiable and should be fair (NS 3.1.14). Common legitimate exclusions include:
- potential participants who lack the capacity to provide valid consent;
- those for whom participation would pose an unacceptable risk;
- those for whom the research or evaluation instruments are not valid (for example, language barriers where translation is not available); and
- minors where the research or evaluation is not designed for children.
Exclusion on the grounds of age, gender, ethnicity, or disability, where these characteristics are not relevant to the research/evaluation questions, requires specific justification. The National Statement is explicit that excluding a group may amount to unfair discrimination and may deprive that group of the potential benefits of participating in research or evaluation, with a consequent impact on the merit of the project (NS 3.1.14).
Over-researched populations
Researchers should consider the degree to which potential participant populations may be over-researched, or may require special consideration or protection, and whether the flow of benefits to that population justifies the burdens of participation (NS 3.1.15). Certain populations, such as Aboriginal and Torres Strait Islander communities, people experiencing homelessness, and people in particular clinical populations, may be subject to heavy research/evaluation demand. This should be considered in recruitment design. At the same time, people must not be denied the opportunity for self-determination or the potential benefits of research or evaluation solely because they belong to a population that may be over-researched or require special consideration (NS 3.1.15; NS 4.1.1(b)).
What reviewers look for
Reviewers expect selection criteria to be traceable to the research/evaluation questions, not asserted in isolation. In practice, this means checking that each inclusion criterion has a stated reason connected to the project's aims, and that each exclusion is justified rather than left as an unexplained default (for example, "adults only" without any indication of whether the topic could apply to younger cohorts). In market research and evaluation, reviewers pay particular attention to convenience-based criteria, such as recruiting only from an existing client list or panel, and will ask whether this narrows the sample in a way that affects the fairness or validity of the findings. Where a population is likely to be over-researched, reviewers look for evidence that this has been considered and, where relevant, that the burden has been weighed against the benefit to that population specifically.
Related resources
- Recruitment strategies: how selection criteria interact with the method of approaching participants
- Avoiding coercion: protecting voluntary participation once eligible participants are identified
- Justice (NS 1.4-1.5): the principle underpinning fair selection and exclusion
- Aboriginal and Torres Strait Islander peoples (NS 4.7): specific guidance for research with populations that may be over-researched
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.