About Systematic Reviews

How Long Does It Take To Do a Systematic Review?

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A systematic review is a study of evidence conducted to answer a specific research question. It uses systematic, explicit, and reproducible methods to identify, choose, and appraise existing research based on predetermined criteria. This data is then extracted and analyzed, to be included in the review. A systematic review involves intensive research, and thus requires a lot of legwork; Completing one can take anywhere between six to eighteen months, depending on several factors including the scope of the topic, the size of the research team, and the steps in a systematic review.

What Is A Systematic Review?

A systematic review is a study that answers a focused research question by employing a comprehensive research strategy that identifies, screens, and evaluates all studies, whether published or unpublished, relevant to the topic. Once all the research is assessed based on strict eligibility criteria (i.e. only qualified studies are included, while others are not), it’s presented as an unbiased and balanced summary of the findings.

Many people wonder, “are systematic reviews qualitative or quantitative?” The answer is that they could be either. A qualitative systematic review uses observation, interviews, or verbal interactions, deriving data from meanings and interpretations of the data collected from the participants. Meanwhile, a quantitative systematic review works with studies that include numerical data. There also are mixed-type reviews which are a combination of quantitative and qualitative reviews.

Steps in a Systematic Review

A systematic review is one of the most rigorous evidence-gathering processes. It starts learning how to choose a topic for systematic review (which usually involves defining a specific research question that hasn’t been reviewed before. If the systematic review is on a topic that has been reviewed before, it should try to fill the gaps identified by the previous review) and ends with writing the paper.

The following are the steps for conducting a review:

  1. Defining the research question
  2. Checking for existing reviews or protocols
  3. Assembling a team
  4. Developing and registering a protocol
  5. Conducting a thorough literature search
  6. Selecting relevant studies
  7. Critically appraising selected studies
  8. Performing data extraction
  9. Assessing, synthesizing, and analyzing results
  10. Interpreting findings
  11. Writing the paper

How Long Does It Take To Do A Systematic Review?

The amount of time it takes to do a systematic review varies. Due to its research-intensive nature, it generally takes between six to eighteen months. This includes going through all the steps in a systematic review previously outlined, as well as the necessary training and meetings required to accomplish the research.

Factors That Affect The Duration Of A Systematic Review

Several factors affect how long it takes to do a systematic review. These include but aren’t limited to

  1. The topic of the review
  2. The number of people in the team and their availability, i.e. if the researchers are doing the study full-time or part-time
  3. Required training
  4. Research methods i.e. the extent of efforts to obtain relevant literature
  5. Availability of studies
  6. Experience of the authors
  7. Support provided to the team


A systematic review is one of the most research-intensive evidence-gathering processes. It involves several steps and, depending on the various factors involved, can take between six to eighteen months to complete. There are no shortcuts to doing it thoroughly. But there are ways to streamline and simplify the process using literature review software such as DistillerSR which allows researchers to automate every step of a systematic review, from literature search, data extraction to auditing. This helps in securely producing evidence-based research faster and more accurately.

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