What Are the Types of IRB Review? Exempt, Expedited, and Full Board Explained

Not all research studies carry the same level of risk — and the Institutional Review Board (IRB) review process reflects that reality. When you submit a protocol for IRB review, the level of oversight assigned to your study depends on the nature of your research, the population involved, and the potential risks to participants. Understanding the different types of IRB review helps you anticipate the review pathway your study will follow, plan accordingly, and avoid costly delays.  

This guide breaks down the three main types of IRB review — exempt, expedited, and full board — and explains how each one works, when it applies, and what distinguishes them from one another. You’ll also find a comparison table to help you quickly identify which review type fits your research. 

Why IRB Review Type Matters 

The IRB exists to protect human research participants. But not every study requires the same level of scrutiny. A low-risk survey study doesn’t need the same oversight as a Phase III clinical trial involving investigational drugs. Assigning the appropriate level of review ensures that protection is proportionate to risk — and that research can move forward without unnecessary administrative burden. 

The three types of IRB review — exempt, expedited, and full board (also called convened review) — each serve a distinct purpose. Knowing the differences can save your team significant time during the planning and submission phase. 

Exempt IRB Review 

What It Is 

Exempt review applies to research that falls within specific categories defined by federal regulations (45 CFR 46.104). Despite the name, “exempt” doesn’t mean the research is free from ethical oversight. If the study qualifies under the specific low‑risk categories, it is exempt from most Common Rule requirements — though any conditions tied to that category still apply, such as privacy safeguards or limited IRB review. 

Researchers cannot self-certify their own studies as exempt. Therefore, a separate entity must make the determination of exemption – in some cases this may be the IRB.  

When It Applies 

Studies may qualify for exempt review if they involve: 

• Educational practices in established settings. 

• Surveys, interviews, or observations of public behavior (with certain conditions). 

• Secondary research using identifiable private information or biospecimens. 

• Benign behavioral interventions with adults. 

• Research involving federal demonstration projects. 

A limited IRB review may be required even for some exempt categories, particularly when studies involve identifiable data and require privacy protections under federal regulations. This limited IRB review confirms that appropriate safeguards are in place without requiring a full committee review.  
 

Key Characteristics of Exemption Status 

• Lowest level of oversight. 

• Determination made by a designated IRB reviewer, not the full board. 

• Ongoing monitoring is generally not required. 

• Re-review is typically not needed unless the study changes significantly. 

Expedited IRB Review 

What It Is 

Expedited review covers research that presents no more than minimal risk to participants and fits within one or more of the federally defined expedited categories. Like exempt review, expedited review doesn’t go before the full IRB committee. Instead, the IRB chair or a designated experienced reviewer conducts the evaluation. 

This pathway balances efficiency with appropriate oversight — making it well-suited for studies that carry some procedural considerations but don’t pose significant risks to participants. 

Expedited Categories 

The Department of Health and Human Services (HHS) has outlined nine expedited categories that qualify for this pathway. For a complete overview, see the official HHS Expedited Review Categories. Some of these include: 

• Collection of blood samples from healthy, non-pregnant adults by venipuncture. 

• Prospective collection of biological specimens for research purposes. 

• Collection of data through noninvasive procedures. 

• Research involving materials collected solely for non-research purposes. 

• Collection of data from voice, video, digital, or image recordings. 

• Research on individual or group characteristics or behavior. 

• Continuing review of previously approved research (under specific conditions). 

• Minor modifications to previously approved research. 

When a study fits within one of these expedited categories, the IRB review process moves faster than full board review — but still maintains meaningful ethical scrutiny. 

Key Characteristics of Expedited Status 

• Applies to minimal-risk research within defined categories. 

• Review conducted by the IRB chair or a designated reviewer. 

• Approval can be granted without convening the full board. 

• Continuing review may be required depending on study duration and type. 

This pathway balances efficiency with appropriate oversight, making it well-suited for studies that require careful consideration but do not pose significant risks to participants. 

Full Board IRB Review 

What It Is 

Full board review (also referred to as convened review) is the most rigorous level of IRB oversight. It applies to research that presents greater than minimal risk to participants or doesn’t qualify for exempt or expedited review. The full IRB committee meets to discuss, evaluate, and vote on whether to approve the research. 

This process exists to ensure that complex, higher-risk studies receive the comprehensive evaluation they require. Multiple reviewers bring different perspectives to the table, which strengthens the quality of the ethical analysis. 

When It Applies 

Full board review is often, but not always, required for: 

• Studies involving vulnerable populations (e.g., children, pregnant women, prisoners). 

• Research with greater than minimal risk to participants. 

• Clinical trials involving investigational drugs, devices, or biologics. 

• Studies that don’t meet the criteria for exempt or expedited review. 

For many clinical trials — particularly those in Phase II, Phase III, or Phase IV — full board review is the standard pathway.  

Key Characteristics of Full Board Review 

• Requires a quorum of IRB members present at a convened meeting. 

• Majority vote needed for approval. 

• Most rigorous level of review and documentation. 

• Continuing review is required at least annually. 

• Conditions or modifications may be required before approval is granted. 

IRB Review Types At a Glance: Comparison Table 

feature	exempt review	expedited review	full board (convened) review
Risk Level	Minimal or no risk	Minimal risk	Greater than minimal risk
Review Process	Designated reviewer	IRB chair or designated reviewer	Full committee at convened meeting
Federal Categories Required	Yes (IRB exemption categories)	Yes (expedited categories)	No — applies when other pathways  don’t
Continuing Review Required	Generally no	Sometimes	Yes, typically annually
Common Study Types	Surveys, interviews, educational research	Blood draws, behavioral studies, minor modifications	Clinical trials, research with vulnerable populations
Approval Timeline	Fastest	Moderate	Longest
Limited IRB Review	Sometimes required	Not applicable	Not applicable

How to Determine Which Review Type Your Study Needs 

The process of determining your review type starts with your IRB submission. Your application should clearly describe the study design, participant population, procedures, data collection methods, and any potential risks. Based on this information, the IRB assigns the appropriate level of review.  

There are a few practical steps you can take to support a smooth determination: 

• Know your population. Research involving children, pregnant women, prisoners, or cognitively impaired individuals is more likely to require full board review. 

• Assess your risk level honestly. Underselling or overstating risk can delay the review process. 

• Review the federal categories. Familiarize yourself with the IRB exemption categories and expedited categories before submission to set realistic expectations.  

• Consult your IRB early. Many institutions and independent IRBs offer pre-submission consultations that can help identify the appropriate pathway before you invest time in a full application. 

Frequently Asked Questions 

Can a researcher determine if their own study is exempt? 

No. While researchers can indicate that they believe their study may qualify for exempt status, other bodies, like institutional offices, can legally make the final determination. Self-certification is not permitted under federal regulations. 

What is the difference between limited IRB review and full exempt review? 

Limited IRB review is a specific type of oversight required for certain exempt categories — particularly those involving identifiable private information or biospecimens. It’s less extensive than full board review, but it ensures that studies include appropriate privacy protections. Not all exempt studies require limited IRB review.  

How long does each type of IRB review take? 

Timelines vary by institution, review type, and IRB workload, with some IRB partners taking up to a few weeks for turnaround. WCG’s turnaround times can be as short as a few days to about a week depending on the type of review. Full board review is typically five to eight days, and expedited review is approximately one to three days. 

Can a study’s review type change after approval? 

Yes. If a study undergoes significant changes — such as adding a new population, modifying procedures, or expanding its scope — the IRB may need to re-evaluate the appropriate review level. What was originally approved as expedited, for example, may require full board review after a major amendment. 

What happens if a study is conducted without IRB review? 

Conducting research without the appropriate IRB oversight can have serious consequences, including loss of federal funding, institutional sanctions, and publication refusals. If there is any uncertainty about the correct review pathway, consult your IRB before proceeding.  

Choosing the Right Path Forward 

If you’re navigating a complex submission, working with an experienced IRB partner can make a meaningful difference. With nearly 60 years of IRB experience, WCG has helped researchers, sponsors, and institutions navigate the review process efficiently and accurately. Receive a free ethical review consultation or have your ethical review questions answered by filling in your information below.