Meta-analyses

Before beginning searching check to see that no one else is doing or has completed a review on the topic to prevent repeating the work of others.

What is already published?

It is possible to find published reviews in databases using a couple of methods:

1. Use database limits or filters to limit your search to review articles.
   • Medline (OVID) - tick the Review articles checkbox that appears in the Limits section underneath the search box
   • Scopus - conduct a search and use the filters to limit results to the Document type - Review
2. When searching include relevant terms in your search strategy such as "systematic review", "scoping review", "literature review" etc.
   • Proquest databases - the review limiter is used to identify book and product reviews. Use keywords in the search for types of reviews instead.

What is currently in progress or being planned?

Check protocol registers to see work in progress.

It is also a good idea to register the protocol in a publicly accessible way as this will also help avoid other people starting a review on the same topic. Once the topic is defined, use the registries listed above to register the protocol as well.

Once the question is developed, do some initial searches to ensure that it is manageable.

Too much
If searches give tens of thousands of results the topic may be too large to manage.
Try to revise the topic to make it more narrow. This may include focusing on one aspect or adding more criteria.
 

Too little
If there are less than a couple of hundred of results then the topic may be too narrow and there may not be enough results to review once inclusion and exclusion criteria are applied.
Try to revise the topic to make it wider. This may include removing some criteria.

Use the Search section of this guide to help devise search strategies and determine where to look for information.