Consent is one of the most foundational requirements in human research ethics. Most evaluators and researchers are comfortable with the basic mechanics: explain the project, give people sufficient information, and obtain their agreement before you collect any data. But what happens when you want to use that data again later, for a different project? Or when you can reasonably anticipate that the data you are collecting today might be valuable for future work that you cannot yet fully specify?
The National Statement on Ethical Conduct in Human Research 2025 (National Statement) has a clear framework for this, and it is more flexible than many evaluators and researchers realise. Understanding it can save you from the costly and time-consuming process of going back to seek fresh consent or applying for a waiver later.
The Three Consent Types Under Paragraph 2.2.14
Paragraph 2.2.14 of the National Statement sets out three types of consent that are available for the use of data in future research:
- Specific consent is the default. It is limited to the project at hand. When you collect data under specific consent, your ethical authority to use that data ends with the project for which it was collected. If you want to use it again, you will need to return to participants or apply for a waiver of consent under the conditions set out in paragraphs 2.3.9 to 2.3.12.
Extended consent covers future use in two defined circumstances:
- projects that are an extension of, or closely related to, the original project (paragraph 2.2.14(b)(i)); or,
- projects in the same general area of research (paragraph 2.2.14(b)(ii)).
- Unspecified consent is the broadest option, covering use of data in any future research. The National Statement is explicit (paragraph 2.2.16) that when unspecified consent is sought, its terms and wide-ranging implications must be clearly explained to potential participants, and that when such consent is given, its terms must be clearly recorded.
Specific Consent Should Be Your Starting Point
Our default position at Iris Ethics is that specific consent is the right choice whenever it is genuinely achievable. It is the most precise form of consent, it gives participants the clearest possible picture of what they are agreeing to, and it minimises the risk of later disputes about whether a particular use of data was actually covered.
We recognise that this position may, at first glance, appear at odds with Paragraph 3.1.49 of the National Statement, which encourages researchers/evaluators to retain data so that it can be used in future studies. Specific consent means that each new use of data, even one that is closely related to the original project, potentially triggers a fresh consent process or, where re-contact is not practicable, a waiver application.
Neither option is cost-free for evaluators and researchers, and a waiver application in particular requires satisfying a number of conditions that may not always be met (for example, that involvement in the research carries no more than low risk, and that there is no known or likely reason to think participants would have objected if asked). This does create a burden. However, this is precisely the gap that extended and unspecified consent are designed to fill.
When Extended Consent Makes Sense
Extended consent is appropriate where there is a sound rationale for anticipated future use, and where that rationale can be communicated clearly enough to participants at the time of the original consent process. The National Statement acknowledges that the necessarily limited information available about future research does not in itself disqualify extended or unspecified consent from being valid (paragraph 2.2.14, final note).
For extensions of the original project (paragraph 2.2.14(b)(i)), the clearest case is programs that operate in rounds, which is a scenario that evaluators working in policy and program evaluation will recognise immediately. Consider a national grants program that runs in three-year cycles. An evaluator engaged to assess Round 3 outcomes may well need to incorporate Round 1 and Round 2 data to understand trends over time: changes to the program guidelines between rounds, the emergence of new applicant types, or shifts in success rates. If the Round 1 and Round 2 data was collected under specific consent, re-contact or a waiver is required. If extended consent was obtained at the outset, covering use in evaluations of subsequent rounds, the problem does not arise.
The same logic applies to longitudinal studies that bring together data from multiple point-in-time projects, and to programs that are progressively scaling in size or geographic scope. Where there is a reasonable expectation at the time of data collection that the project will continue or expand, extended consent is a sensible pre-emptive step.
For data in the same general area (paragraph 2.2.14(b)(ii)), the language in the National Statement is admittedly vague. In practice, however, this is less of a problem than it first appears. Data collected in one project is, in most cases, only likely to be useful in similar lines of evaluation or research. Examples include meta-evaluations that draw on individual-level data from multiple prior program evaluations to assess what works across a class of interventions, or social research projects that involve comparative analysis of different program designs using data previously collected from participants in each program. The practical scope of "the same general area" is constrained by what data is actually useful for, which keeps the risk of this consent type being stretched unreasonably quite low.
Aggregated and Published Data
One important clarification is worth making explicit. The consent considerations above relate specifically to scenarios involving individual-level data from previous projects. Where a future project draws only on published reports or aggregated findings, there is no extension of consent required at all.
If participants consented to aggregated analysis and publication of findings as part of the original project, then a subsequent project that uses those published findings is not going beyond the original consent in any meaningful sense. No additional consent mechanism is needed. This is a distinction that evaluators and researchers sometimes overlook, and recognising it can avoid unnecessary complexity in ethics applications.
Documentation Is Not Optional
For extended or unspecified consent to be effectively obtained, the consent process and its rationale must be well-documented from the outset. Paragraph 2.2.16 requires that the terms of unspecified consent be clearly recorded. Paragraph 2.2.17 requires that any subsequent reliance on existing unspecified consent in a new ethics application must describe the terms of that original consent.
In practice, this means two things:
- Your participant information sheet and consent form need to clearly articulate the scope of the consent being sought and what future uses might look like, to the extent these can be anticipated.
- When you submit a future ethics application that relies on consent already given, you need to be able to point to evidence that the consent covered the proposed use. This is where thorough documentation at the original project stage pays dividends.
Paragraph 2.2.18 is also worth keeping in mind. If a future project needs to collect data that goes beyond what the original extended or unspecified consent covered, fresh consent (or a waiver) is still required for that additional material. Extended and unspecified consent are not blank cheques.
What Ethics Committees Look For
When reviewing applications that propose to rely on extended or unspecified consent given in a prior project, the focus should be on two questions:
- Does the proposed use fall within the terms of the original consent?
- Is there adequate documentation to substantiate that the consent was properly given and that its terms were understood by participants?
Applications that answer both questions clearly should satisfy review requirements. Where documentation is thin or the proposed use appears to stretch the scope of the original consent, that is the point to seek further information from the applicant.
Getting the Balance Right
The consent framework in paragraphs 2.2.14 to 2.2.18 of the National Statement exists to give evaluators and researchers realistic options for managing data across multiple projects while still protecting the interests of participants. Specific consent remains our default, but the extended and unspecified consent provisions are legitimate tools when the rationale is sound and participants are genuinely informed.
The key questions to ask yourself when designing your consent process are:
- Is there a realistic prospect that this data will be useful in future work?
- Can I describe that prospect clearly enough that participants can make an informed decision?
- Will I document the process thoroughly enough to rely on it later?
If the answer to all three is yes, extended or unspecified consent may well be the right choice.
Want to know more about how these consent provisions apply to your specific project or program evaluation? Reach out to the Iris Ethics team.
AI Disclosure: Initial drafts of the content for this article were prepared using Large Language Models (Claude Sonnet 4.6) 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.