In a standard systematic review, researchers conduct a comprehensive search for relevant studies. This includes using multiple databases, seeking research in every language, and even digging for unpublished “grey literature.”
All of this searching takes time, and depending on the topic under review, may result in potentially hundreds or thousands of relevant studies to screen, and sometimes several hundred articles from which to extract data.
If you’re looking to speed up your review, you could consider limiting your search.
Here are some typical ways to restrict your search:
- Just look for published, peer-reviewed studies (vs. unpublished and “gray literature”)
- Search one or two databases (vs. multiple) that are most relevant to your topic
- Search within a specific timeframe (e.g., the last 10 years vs. all time)
- Prioritize relevant studies (e.g., research from the same region or most related to your question)
- Use established search filters to find specific types of studies (e.g., search only for systematic reviews or randomized controlled trials). Just remember, filters can be imperfect. It is possible you’ll miss important and relevant studies because of the way your filters were coded.
Consequences of this shortcut
Restrictive searching can dramatically reduce the number of studies you have to screen, extract, summarize, and, where relevant, meta-analyze. This can save time, but it can also significantly undermine the robustness of your review, so consider this decision carefully. You will no longer be able to claim that you’ve offered a comprehensive picture of the evidence.
It is important to involve an experienced Information Specialist, who can help you design your search strategy.