IRB approval is required before human subjects research can commence. That approval can be obtained from an institution’s internal IRB or from an external IRB, such as a commercial IRB or an IRB at another institution. The IRB completing the review is called the “reviewing IRB,” and institutions that rely on an external IRB are called “relying institutions.”

When a study is subject to an sIRB review model, the investigators must identify a specific IRB to serve as the reviewing IRB (or “IRB of record") for the study. The proposed IRB must agree to serve in this role, and an IRB can refuse to serve as an sIRB.

Participating sites must agree to the use of the designated sIRB and complete a formal reliance agreement which cedes IRB review to the reviewing IRB. As noted below, the relying institutions retain a number of responsibilities beyond IRB approval.