Direct comparison
Minimal Risk vs Greater Than Minimal Risk
How 45 CFR 46 defines minimal risk, why the distinction drives IRB review pathway, consent waivers, and children's research categories, with examples.
Side-by-side comparison
| Dimension | Minimal Risk | Greater Than Minimal Risk |
|---|---|---|
| Regulatory definition | Defined at 45 CFR 46.102(j): harm or discomfort no greater, in probability and magnitude, than those ordinarily encountered in daily life or during routine physical/psychological exams. | Not separately defined. Any research whose anticipated probability or magnitude of harm exceeds the 46.102(j) threshold; a residual, case-by-case IRB judgment, not a fixed numeric scale. |
| IRB review pathway | May qualify for expedited review (45 CFR 46.110 / 21 CFR 56.110) if it also fits one of the nine enumerated categories — reviewed by the chair or designated experienced reviewer(s), not the full board. | Must go to full board (convened) review under 46.108 — a quorum voting at a scheduled meeting. The only pathway that can approve greater-than-minimal-risk research or disapprove any study. |
| Continuing review | Not required at all for expedited-eligible research, per 46.109(f) (2018 Common Rule revision), unless the IRB determines otherwise. | Required by the convened board at intervals appropriate to risk, at least annually (46.109(e)) — no exception available. |
| Consent-waiver eligibility | Meeting this threshold is the first of five required findings under 46.116(f)(3) for an IRB to waive or alter informed consent. | Categorically ineligible for a consent waiver, regardless of how the other four 46.116(f)(3) criteria are met. |
| Children's research category (Subpart D) | Falls under 46.404 — IRB may approve with one parent’s/guardian’s permission plus the child’s assent where appropriate. | Falls under 46.405 (direct-benefit prospect) or 46.406 (no direct benefit, but minor increase over minimal risk plus generalizable-knowledge finding); 46.406/46.407 research generally requires both parents’/guardians’ permission. |
| Exemption eligibility (46.104) | Several of the eight exempt categories are built around a no-more-than-minimal-risk standard (e.g., benign behavioral interventions, limited-IRB-review secondary-use categories). | Not eligible for exemption under any category once risk exceeds the minimal-risk threshold. |
| Monitoring expectations | Typically tracked through the standard IRB continuing-review cycle, where applicable. | Increasingly expected to have a dedicated, independent monitoring structure (e.g., a Data Safety Monitoring Board) scaled to risk and complexity, especially for multi-site trials. |
| Typical examples | Single small-volume blood draw, validated survey on non-sensitive topics, routine vision/hearing screening, secondary analysis of de-identified records. | Investigational drug/device with unknown side-effect profile, invasive diagnostic procedure, sham-control arm, intervention risking significant or lasting psychological distress. |
Common questions
FAQ
Who decides whether a study is minimal risk or greater than minimal risk?+
The IRB makes this determination, not the investigator — it's a required finding the IRB must document before approving any protocol (45 CFR 46.111(a)(2)), and it drives which review pathway, consent rules, and (for pediatric research) permission structure apply.
Is "greater than minimal risk" defined anywhere in the Common Rule?+
No. 45 CFR 46.102(j) defines only "minimal risk." "Greater than minimal risk" is used throughout the regulation (e.g., 46.108, 46.405-46.407) as the residual category above that threshold, but it has no independent regulatory definition of its own.
Can a single study include both minimal-risk and greater-than-minimal-risk procedures?+
Yes — many protocols combine a minimal-risk baseline (like a questionnaire) with a higher-risk intervention (like an investigational drug). The IRB classifies and reviews the protocol as a whole based on its highest-risk component, not an average across procedures.
Does "greater than minimal risk" mean a study is unsafe?+
No — it's a regulatory classification, not a safety verdict. Most clinical trials and a great deal of valuable biomedical research fall into this category; the classification exists to trigger proportionately stronger IRB oversight (full board review, mandatory continuing review, no consent waiver), not to discourage the research.
