It is important to ensure that your research question has not already been answered in a recent review. 

There are a number of organizations that list prospective, on-going, and published reviews.

Within business:

• Campbell Collaboration
• EPPI-Centre

Within education:

• Campbell Collaboration
• Education Endowment Foundation
• EPPI-Centre
• Swedish Institute for Educational Research (Skolforskningsinstitutet)
• What Works Clearinghouse (WWC) from the Institute of Education Sciences (IES)

Within health and welfare:

• Best Evidence Medical and Health Professional Education Collaboration (BEME)
• Campbell Collaboration
• Cochrane
• EPPI-Centre
• Epistemonikos
• Health Services Research Projects in Progress (HSRProj)
• PROSPERO International Prospective Register of Systematic Reviews
• Swedish Agency for Health Technology Assessment and Asessment of Social Services (SBU)

Other disciplines:

• Collaboration for Environmental Evidence (CEE)
• International Initiative for Impact Evaluation (3ie)

You can check for published reviews or protocols with a quick search in Google Scholar. Test entering keywords from your research question together with terms like: scoping review, systematic review, meta-analysis, meta-synthesis, review protocol.

Test entering keywords from your research question together with phrases like: scoping review, systematic review, meta-analysis, meta-synthesis, review protocol.

Alternatively, you can test entering your keywords and using the filter for document type in Scopus.

Test entering keywords from your research question together with phrases like: scoping review, systematic review, meta-analysis, meta-synthesis, review protocol.

For example in PubMed:

Alternatively, test entering keywords from your research question and using any of the filters the database provides for reviews. 

For example in PubMed:

For example in MEDLINE (EBSCOhost):