When the IRB approves your study, it is required by regulation to make certain determinations. Two criteria the IRB must be able to be able to document as being met are that risks to subjects are minimized by using procedures consistent with sound research design, and that selection of subjects is equitable (45 CFR 46.111).
To be able to make those determinations, a complete description of the study’s proposed procedures needs to be included in the protocol document, and the rationale for choosing your particular subject population needs to be clear. When we send protocols back with contingencies asking for more details about your procedures or your study population, it’s because we feel we don’t have enought detail to make the required determinations. Research teams try to tell us that they don’t need to put it in their protocol because that’s the way it’s always done, or that it’s already perfectly clear to people familiar with this line of research. While we know that you have a lot of the background in your head, these kinds of details need to be written down in your protocol as well. If the IRB is ever questioned by a regulatory agency or our accrediting body about its procedures, that level of detail is essential to our showing that we are meeting requirements designed to maximize subject safety.