A research protocol, research proposal, or review protocol, is a document that states what you plan to do and how you plan to do it.
Starting with a structured, detailed, and written research protocol will help ensure that your methodology is systematic, thereby reducing sources of bias at various stages of your review.
The protocol should include your focused research question and describe the methods you will be using to conduct your review.
For example, the content of a research protocol would include:
A more detailed list of the elements of a protocol can be found in the Cochrane Handbook.
Keep in mind that after your initial literature search you may find the need to revise your protocol. Make sure to document any changes that have been made to the protocol in the methods section of the completed review.