Research with children is held to stricter rules than research with adults, for good reasons. Children can't always weigh risks for themselves, they depend on adults, and harm in childhood can last. This guide explains how those protections work, why they shape what researchers can study, and what to ask if your family is invited to take part.
This is a general overview, not legal advice. Rules vary between countries and institutions, and the details below focus mainly on the United States, with notes on common international practice.
Why ethics rules shape the evidence
Ethics rules are one reason the research on children looks the way it does. Many of the questions parents most want answered, about divorce, poverty, bullying or early screen exposure, can't be studied with a randomized trial, because no ethics committee would approve assigning children to harm. Researchers use observational designs instead, with the limits explained in the study types guide.
So when a study "only" shows an association, sometimes that's the strongest design that could ethically be run.
Permission and assent
Two kinds of agreement usually apply.
Parental permission comes from a parent or legal guardian, who agrees that their child can take part. Researchers have to explain the study's purpose, what the child will do, the risks and benefits, how data will be kept, and that taking part is voluntary.
Assent is the child's own agreement. It's sought when a child is old enough to understand what's being asked, which in practice often means from around school age, with explanations adapted to the child's age. A seven-year-old might get a short, picture-based explanation; a fifteen-year-old, something close to the adult version. Silence or failing to object isn't assent.
When a young person reaches the age of majority during a long-term study, researchers generally need to ask them directly for consent to continue.
Ethics committees
Before a study with people can begin, an independent committee reviews it. In the US these are called institutional review boards (IRBs); elsewhere they're often research ethics committees or boards. Members usually include scientists, non-scientists and someone from outside the institution.
The committee checks that risks are as low as possible, that they're reasonable compared with the expected benefits, that participants are chosen fairly, that the consent process is clear, and that privacy is protected. It can ask for changes, approve or reject a study, and must approve changes made later.
How US rules grade risk
In the US, federally funded research follows a set of regulations known as the Common Rule (45 CFR 46), which has a section, Subpart D, with extra protections for children. It sorts research into categories by risk:
- Minimal risk. Risks no greater than those of everyday life or routine exams, such as a short questionnaire or a standard reading test. This can be approved with permission from one parent and the child's assent.
- More than minimal risk, with a direct benefit to the child. For example, a trial of a treatment the child might gain from. The risk has to be justified by the expected benefit.
- A minor increase over minimal risk, with no direct benefit, but likely to produce important knowledge about the child's condition. Usually requires permission from both parents where reasonably possible.
- Research that doesn't fit the other categories but might help understand or prevent a serious problem affecting children. This needs special review at the federal level.
Other countries use different frameworks, but most share the same ideas: higher risk needs stronger justification, and children who can't benefit directly should only be exposed to small risks.
Privacy and data
Studies with children collect sensitive information: school records, health data, family circumstances, sometimes recordings. Ethics review looks at how this is stored, who can see it, how long it's kept and whether it's shared with other researchers.
Two terms come up often. Anonymous data can't be linked back to a person at all. Pseudonymized or coded data has names removed but can be re-linked by someone holding a key. Coded data is common and acceptable, but it isn't the same as anonymous, and consent forms should say which applies.
Privacy has a second side. If a child tells a researcher they're being harmed, most studies have a plan for passing that on to someone who can help. Good consent forms explain where confidentiality ends.
Research in schools
Much research with children happens in schools, which raises its own questions. Schools may give permission for a study to run on their premises, but that doesn't replace parental permission for individual children in most cases. Some minimal-risk school surveys use an "opt-out" approach where parents are informed and can refuse; whether this is acceptable depends on local rules and the ethics committee.
Children in a classroom may also feel pressure to join because their friends are. Good studies give children a real alternative activity and make it easy to decline without anyone noticing.
Payment and incentives
Studies sometimes offer families money, vouchers or small gifts. Modest payments to thank people for their time are normal. Ethics committees look out for payments large enough to persuade families to accept risks they otherwise wouldn't, and some prefer that children's own rewards be small and age-appropriate.
Online research
More research now happens online, through apps, social platforms or online surveys. This makes it harder to confirm a participant's age or that a parent agreed. Researchers and ethics committees have developed approaches for this, but readers should be a little more cautious about online samples of "teenagers" where ages were self-reported.
If your child is invited
Before saying yes, it's reasonable to ask:
- Who is running the study, and which ethics committee approved it?
- What exactly will my child do, and how long will it take?
- What are the risks, including discomfort or upsetting questions?
- What will happen to the data, and who will see it?
- Can we stop at any time, and does stopping affect services or grades?
- Will we hear about the results?
Researchers should be glad to answer. If they aren't, that's useful information.
Reading ethics statements in papers
When you read a study, look for the ethics statement. It's often short: a committee name, a reference number and a note on how consent was obtained. Its absence isn't proof of wrongdoing, especially in older papers, but in modern research with children it should be there. The study checklist doesn't score ethics directly, but a missing statement is a reason to look harder at everything else.
The next guide, finding open-access research, explains how to read the full paper, including that ethics statement, without paying.
Questions readers ask
- Can my child take part in a study without my permission?
- In most research, no. Parental permission is the normal rule. Ethics committees can sometimes approve exceptions, for example for minimal-risk anonymous surveys or where asking a parent could put a young person at risk, but these are reviewed case by case and the rules differ between countries.
- Can a child say no even if the parent says yes?
- In general, yes. Ethics rules ask researchers to seek a child's assent when the child is old enough to understand, and a child's refusal is usually respected. A narrow exception can apply when a study offers a direct health benefit the child can't get elsewhere.
- How do I check whether a study was ethically approved?
- Published papers normally state which ethics committee or institutional review board approved the study, often with a reference number, near the methods or at the end. If you are asked to enroll your child, you can ask the research team for that information before agreeing.