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Systematic Reviews: Home

What is a Systematic Review?

A systematic review is a type of  review that seeks to collect, critically appraise, and synthesize all of the evidence answering a given research question.The goal here is to collect and review all empirical evidence that matches a pre-selected eligibility criteria to answer a specific research question. The methods used are explicit in order to minimize bias, and are clearly documented and reproducible. 

A meta-analysis is the statistical analysis conducted within a systematic review, combining the results of multiple studies. 

A systematic review is a qualitative analysis of the literature and findings of all studies on a topic. A meta-analysis is the quantitative analysis of the data and findings of all studies on a topic. 

Steps in a Systematic Review

1. Check to see if a systematic review has already been done for your proposed research question.

2. Create a review protocol

3. Build a review group

4. Formulate your question(s)

5. Conduct a thorough search of the literature

6. Select the relevant studies (based on pre-determined criteria)

7. Appraise the quality of the studies

8. Pull information from individual studies

9. Synthesize studies

10. Report what is known and unknown

11. Inform research, policy, and practice


What is Required?

A systematic review is a thorough and complete review of research on a given topic. Researchers performing a systematic review should create their review protocol which includes their PICO question, search strategy, selection criteria, data extraction procedure, data synthesis procedure, and project timetable. 

The goal with a systematic review is to gather all the existing body of evidence on a topic and work within the review protocol to select studies that fit within the precise criteria being reviewed. 

Key requirements for a systematic review are:

  • A review team or group. This should include experts on the topic being reviewed if possible. A librarian may also be part of a review group and depending on the role, authorship may be requested.
  • A review protocol that includes the item listed above. This should be compiled prior to any searching. PRISMA-P offers guidance to create a review protocol.
  • A plan for data synthesis, whether it is qualitative or quantitative in nature. For systematic review qualitative synthesis, a plan for who will review studies, the criteria under which they will be reviewed, and how to handle conflicting researcher reviews of a study should be addressed. It is best practice to have more than one member of a review team review every study and determine whether or not it should be included. In cases of reviewers disagreements, either a plan to discuss disagreements and resolve them or a third party not associated with the review should be consulted. For meta-analysis where quantitative data needs synthesized and analyzed, a statistician who can assist with questions or concerns is also a recommendations. 
  • Documentation of the review process that includes steps taken and reasoning for excluding studies. 

Sample Timeline for a Systematic Review

Systematic reviews are time consuming research projects and require a lot of effort and dedication. A typical timeline is around 1 year from start to finish. The Cochrane Handbook for Systematic Review and Interventions offers the following timeline:



1 - 2

Preparation of protocol

3 - 8

Searches for published & unpublished studies

2 - 3

Pilot test of eligibility criteria

3 - 8

Inclusion assessments


Pilot test of “Risk of Bias” assessment

3 - 10

Validity assessments


Pilot test of data collection

3 - 10

Data collection

3 - 10

Data entry

5 - 11

Follow up of missing information

8 - 10


1 - 11

Preparation of review report

12 -

Keeping the review up-to-date


Other Types of Reviews

Scoping Review - these types of reviews are topic based reviews that function as preliminary assessments to determine the size and scope available on a topic. They usually take a year to complete and involve structured searches and aim to identify and clarify definitions and boundaries of a topic.

Rapid Review - similar to systematic reviews, but with a shortened time frame. These types of reviews speed up the systematic review process by eliminating some of the stages to make the review less rigorous. Rapid reviews take roughly 5 weeks (200 hours) to complete and methods can vary widely.

Mixed Studies (methods) Review -  this is a specific approach to conducting a systematic review that combines findings of both qualitative and quantitative studies into a single systematic review. These take 12-18 months to complete.

Literature Review - this type of review is a critical evaluation of the literature available on a topic. Goals here are to identify and critique the existing literature and provide a review of the existing knowledge on a topic as well as any gaps in the literature. These can be stand-alone review articles, or part of a larger review. Time frames vary depending on the topic, available resources, and goal of the review.