Systematic review protocol

Develop a protocol for a systematic review. Your protocol should be structured using an appropriate reporting guideline/template (such as PRISMA-P).

You will:

provide a succinct background that presents the rationale for the review in the context of what is already known;

provide a clear and explicit statement of the question(s) the review will address (and check that there is no existing recent review addressing your proposed question);

describe the study characteristics/eligibility criteria for included studies (structured using a tool such as PICO(S) or SPIDER);

describe all intended information sources (such as electronic databases, contact with study authors, trial registers or other grey literature sources);

present a full draft search strategy to be used for at least one electronic database (such that it could be repeated);

state the process that will be used for selecting studies (such as two independent reviewers) through each phase of the review (i.e. screening, eligibility and inclusion in meta-analysis);

list and define all variables and outcomes for which data will be sought (data items), and describe the method for data extraction, and any processes for obtaining and confirming data from authors;

describe the methods for quality appraisal (assessing risk of bias) for individual studies (including reference to appropriate quality appraisal checklists);

describe the approach to synthesising the findings of included studies, and any analyses that will be carried out (if data are appropriate for quantitative synthesis (meta-analysis), describe planned summary measures, methods of handling data and methods of combining data from studies).

The protocol should be no more than 3,000 words in length.