Definition

A systematic review is document often written by a panel that provides a comprehensive review of all relevant studies on a particular clinical or health-related topic/question. The systematic review is created after reviewing and combining all the information from both published and unpublished studies (focusing on clinical trials of similar treatments) and then summarizing the findings.
A Protocol submitted to Prospero is usually required.

Do not confuse it with a Scoping Review.
 

Goal of a Systematic Review

The aim of a systematic review is to answer a specific question. For instance, a question might be: 'How effective is laser therapy in the treatment of a recently sprained ankle? ' The research question can be specified by indicating exactly which population, intervention, and outcome is of interest. A decision for patient care.
 

Advantages

• Exhaustive review of the current literature and other sources (unpublished studies, ongoing research)
• Less costly to review prior studies than to create a new study
• Less time required than conducting a new study
• Results can be generalized and extrapolated into the general population more broadly than individual studies
• More reliable and accurate than individual studies
• Considered an evidence-based resource

Disadvantages

• Very time-consuming--plan for a minimum of 8 months of work, if not longer
• May not be easy to combine studies. Primary research studies, i.e. published, unpublished (gray literature), cohort, and RCTs are all acceptable evidence it include in review process. Review papers (literature, narrative, integrative, etc) are not acceptable to include.
   

Design pitfalls to look out for

Studies included in systematic reviews may be of varying study designs, but should collectively be studying the same outcome.

Is each study included in the review studying the same variables?

Some reviews may group and analyze studies by variables such as age and gender; factors that were not allocated to participants.

Do the analyses in the systematic review fit the variables being studied in the original studies?