Direct comparison
Informed Consent vs. Assent | 45 CFR 46.408
Informed consent vs. assent in pediatric research: who gives each, the 45 CFR 46.408 assent rule, IRB age conventions, and when assent can be waived.
Side-by-side comparison
| Dimension | Informed consent / permission | Assent |
|---|---|---|
| Who gives it | Competent adult participant, or a parent/guardian on a child's behalf | The child participant themselves |
| Governing provision | 45 CFR 46.116 (general); 46.408(b) (parental permission) | 45 CFR 46.408(a) |
| Legally sufficient alone to enroll a child | Parental permission alone is not sufficient if the child is capable of assenting | Assent alone is never sufficient — parental/guardian permission is still required |
| Capacity standard | Presumed adult legal capacity, or parental legal authority | IRB-determined developmental capacity (age, maturity, psychological state) — no fixed regulatory age |
| Satisfied by silence/non-objection | No | No — 46.408(a) explicitly excludes mere non-objection |
| Can be waived | Yes, under 46.116(f) / 46.408(c) conditions | Yes, under 46.408(a) — limited capacity, or a direct-benefit intervention available only via the research |
| Documentation | Signed form under 46.117, unless waived | No fixed format under 46.408(e) — commonly age-appropriate written or verbal documentation set by the IRB/protocol |
| Typical age convention | Not age-gated for a legal adult/guardian decision-maker | Commonly expected from roughly age 7 up, per IRB convention — not a number fixed in the regulation |
Common questions
FAQ
Can a child's assent replace parental permission?+
No. Under 45 CFR 46.408, assent and parental/guardian permission are independent, cumulative requirements. Except where the IRB specifically waives parental permission (46.408(c)) or specifically waives assent (46.408(a)), a pediatric study generally needs both.
At what age is assent required?+
45 CFR 46.408 does not set a fixed age — it directs the IRB to judge whether a child is capable of assenting based on age, maturity, and psychological state, either for the whole protocol or child by child. Many US IRBs use roughly age 7 as a practical starting point for beginning to seek assent, with adolescents around 14+ sometimes signing the same document used for consent, but this is institutional convention built on the regulation's language, not a number written into 46.408 itself.
Can an IRB waive the assent requirement?+
Yes. Under 46.408(a), the IRB may find assent is not required if the children's capability is so limited they cannot reasonably be consulted, or if the research offers a prospect of direct benefit important to the child's health that is available only through the research. Assent can also be waived under the same general conditions (46.116(f)-type criteria) that permit waiving consent more broadly.
Is a child's cooperation during a procedure the same as assent?+
No. Assent requires an affirmative agreement process the IRB has approved in advance — going along with a procedure, or simply not objecting, does not meet the 46.408(a) standard on its own.
Going deeper
