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Determine Your Timeline

In general, investigators should plan to submit a complete application for IRB review at least two months prior to beginning low risk studies. Researchers planning studies with vulnerable populations or other greater than minimal risk research should plan to submit at least six months prior to beginning the study.

Submissions to the IRB are processed and reviewed on a first-come, first-served basis.  Failure to plan for the IRB review process may delay your timeline for the initiation of the research.  No research activities involving participants or identifiable data, including recruitment, may begin until final IRB approval or an exempt determination is granted.

Most studies are reviewed outside of the convened IRB (as exempt or expedited) and can be submitted at any time.  Studies that are reviewed at scheduled IRB meeting involve greater than minimal risks to participants and need to submit well in-advance of a scheduled meeting to make that agenda.  More information on the review processes can be found in this Guidance section of the website.  The level of review is determined by the HSPP/IRB based on your protocol and cannot be requested by the researchers.


Factors that influence the speed with which a protocol can be reviewed include the following:

  • Risks to participants. Low risk studies can be read by one or two reviewers while higher risk studies require more reviewers or a full-panel review.
  • Complete information. Follow the information in the Investigator Manual to ensure that you are submitting a complete application for IRB review.  Create a new project and submit materials for review in IRBNet.  Incomplete submissions will not be assigned for review, until all materials are complete.  Missing information or documentation will delay the review process.
  • Attention to detail.  Creating a clear and detailed submission packet will greatly impact the reviewer's ability to make a determination in a timely manner.  Information presented in more than one place, in the protocol and in the consent form for example, should be consistent.  Where there are inconsistencies, the reviewer often has to request clarification or further information to ensure that the regulatory requirements are being met.  Reviewers cannot make determinations based on assumptions, so clearly and consistently state your research plan throughout all your submission materials.

Many protocols are not approved on the first review because there are questions or concerns about the content.  After the initial review, the Principal Investigator will receive a notice via IRBNet.  Determination letters are not the same as approval letters.  Investigators may receive a determination letter requesting modifications that must be re-reviewed before the protocol can be approved.  The HSPP staff can answer questions about IRB requests for modifications or clarification and can offer guidance on how to revise your submission materials accordingly.

If you are new to the IRB review process or if you have any questions as you develop your submission materials, please contact the HSPP for assistance and answers at hspp@msudenver.edu.


If your study may require full Board review, please take note of the meeting schedule and be advised that a complete submission would need to be received at least two weeks prior to the scheduled meeting date in order to make the meeting agenda.  We recommend that studies that may require full IRB review be submitted at least six months prior to the planned start date of the research.