A protocol for a review describes the rationale, and planned methods for the review. It must be prepared before the review is started, and registered in a registry such as PROSPERO or Open Science Framework (see below). A protocol is like a blueprint for a house; your research team will use it to guide them through each step of the process.
"85% of research investment is estimated to be lost because the wrong questions are asked, inappropriate research designs/methods are used, poor regulations are in place, or researchers incompletely/inadequately report their research, or fail to publish it at all." PRISMA-P
Completing a protocol means that the you will have searched for other similar reviews, and developed a rationale or justification for why your review is necessary. It also means that you will have taken time (up to 3 months) to prepare each step of your review, including eligibility criteria, data extraction and quality assessment tools, and the research questions. Ultimately, it will improve the transparency and reproducibility of your review, and ensure that you are not duplicating efforts already done.
Registering your protocol will improve transparency as well as alerting other researchers of your intentions so efforts are not duplicated.
If you choose Level 3: Co-authorship to do your project with a librarian, we require that your protocol is registered before we begin our searching.