03 · What You Need to Know
Voluntary participation does not mean every procedure is negotiable
Informed consent gives prospective participants a meaningful choice about whether to enter research. Under HHS regulations, participants must be informed that participation is voluntary, refusal involves no penalty or loss of benefits to which they are otherwise entitled, and participation may be discontinued without such penalty or loss.
That principle is sometimes misunderstood as requiring researchers to let participants select whichever pieces of the protocol they prefer.
It does not.
Researchers can define what the study actually is
A research protocol is designed to answer a particular question using specified procedures.
If randomization is essential to a randomized controlled trial, someone who refuses randomization is declining that trial. If repeated blood sampling is necessary for the primary outcome, a person who refuses all blood draws may not be able to participate.
This does not violate voluntariness. The participant remains free to say no to the research.
Consent gives the participant authority over whether to participate. It does not necessarily give them authority to redesign the study.
The requirement should have a genuine connection to the research
The harder cases arise when a study makes participation conditional on activities that are not obviously necessary for the primary research.
Suppose participation in a questionnaire is made conditional on agreeing to receive recruitment messages for unrelated future studies. Or participation in a current study requires permission to use identifiable photographs in future presentations even though the photographs are unnecessary for the current analysis.
In those cases, researchers should ask why the additional agreement needs to be mandatory.
The fact that obtaining the permission now would be convenient is not the same as demonstrating that the activity is necessary for the research.
Scientific necessity is not simply researcher preference
Researchers should be able to explain why refusing a procedure would prevent participation.
A useful test is to ask what would happen scientifically or operationally if the participant declined it.
Would the primary outcome become impossible to measure? Would the intervention no longer be delivered as designed? Would the participant's inclusion violate the protocol or compromise safety? Would the study no longer answer the question for which ethics approval was obtained?
If none of these or another substantive reason applies, the argument for making the activity mandatory becomes weaker.
Necessary condition of participation
A procedure or requirement integral to conducting the approved research with that participant.
Convenient additional permission
An activity useful to the research team but separable from participation in the main study.
Voluntariness also depends on what happens if someone refuses
A study may legitimately have eligibility requirements. But researchers must still consider whether declining participation carries an inappropriate penalty or loss of benefits to which the person is otherwise entitled.
OHRP emphasizes that consent circumstances should minimize coercion and undue influence. Authority relationships can complicate this, particularly when participants are employees, students, patients, or others who may believe refusal has consequences beyond research eligibility.
For example, saying "You cannot join this trial unless you accept randomization" is different from saying "You cannot receive your ordinary clinical care unless you join this trial."
The first may describe the nature of the research. The second raises a much more serious voluntariness problem if ordinary care is otherwise available.
Refusing research should not improperly affect ordinary care
The 2024 Declaration of Helsinki states that refusal to participate in research, or a decision to withdraw, must never adversely affect the patient-physician relationship or provision of the standard of care.
This distinction is especially important when research is embedded in clinical care.
A patient may be required to accept all core procedures if they want to enter a particular trial. They should not be led to believe that refusing the trial means forfeiting ordinary care to which they would otherwise have access.
Optional components should be identified as optional
If a protocol allows a participant to decline an activity and still join the main study, consent materials should not imply that the activity is mandatory.
Possible examples include future contact, some ancillary studies, additional specimens, certain recordings, or future uses of data and specimens, depending on the protocol and applicable framework.
Whether participants can consent to some components while refusing others should therefore be determined during study design and ethics review.
Bundling can undermine meaningful choice when the components are separable
Bundling means placing multiple permissions into a single all-or-nothing decision.
Bundling is not inherently wrong. Core procedures often need to be bundled because together they constitute the study.
The concern arises when materially different and separable activities are bundled solely so that participants cannot refuse one without losing access to another.
For example, a research team might reasonably require permission to collect the data necessary for the primary study. Requiring permission for unrelated future marketing communications would be a very different proposition.
The appropriate boundary depends on the activity and governing requirements rather than the mere fact that everything can fit on one form.
Future data and specimen use deserves particular care
Research participation increasingly creates data or biological materials that may remain valuable after the original study ends.
Researchers should not assume that consent to the present study provides unlimited permission for all later uses.
The 2024 Declaration of Helsinki requires informed consent for the collection, processing, storage, and foreseeable secondary use of biological material and identifiable or re-identifiable data in medical research.
OHRP advisory material concerning biospecimens and associated data likewise discusses the need for meaningful information about future research uses and cautions against treating a bare future-use checkbox as necessarily sufficient.
Whether future use can be required as part of participation, offered separately, covered through broad consent, or conducted under another lawful pathway depends on the study and regulatory framework.
Publication is not necessarily the same consent question as participation
Researchers ordinarily conduct studies intending to analyze and disseminate findings. Participants therefore should receive appropriate information about how research results and their information may be used.
But publication can create separate issues when material could identify an individual, such as recognizable photographs, detailed case information, quotations, or other identifiable content.
Researchers should not assume that consent to participate automatically resolves every consent question about publication.
Making something mandatory can affect recruitment fairness
Every additional mandatory activity can narrow who is willing or able to participate.
Sometimes that is unavoidable. A study may simply require the procedure.
But unnecessary bundling can systematically exclude people who are comfortable with the core research but uncomfortable with a secondary activity. That may affect recruitment, participant diversity, and the ethical justification for the consent design.
Researchers should therefore distinguish necessary exclusions from exclusions created merely by administrative convenience.
The protocol should settle these boundaries before recruitment
Researchers should not negotiate mandatory procedures differently with each participant unless the approved protocol explicitly allows such flexibility.
Doing so can create inconsistent study procedures, compromise data integrity, and produce consent promises that the research team cannot reliably implement.
The protocol and ethics-review materials should identify core activities, optional components, relevant participant choices, and how those choices will be recorded.
Watch Out
Do not label a procedure "required" merely because the research team would prefer everyone to agree to it. If refusal would not undermine the approved study, participant safety, or another substantive requirement, consider whether making it mandatory is genuinely justified.
