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Systematic Reviews in the Health Sciences

What is a systematic review?

Question marks

  Questions by Russ Allison Loar

A Systematic Review is a review of a clearly formulated question that uses systematic and reproducible methods to identify, select and critically appraise all relevant research, and to collect and analyse data from the studies that are included in the review. A systematic review can be either quantitative or qualitative.

A quantitative systematic review will include studies that have numerical data. A qualitative systematic review derives data from observation, interviews, or verbal interactions and focuses on the meanings and interpretations of the participants. It will include focus groups, interviews, observations and diaries.

Systematic review or literature review

The table below will help to differentiate between a systematic review and a literature review

Systematic Review

Literature review


Focused on a single question

An overview not necessarily focused on a single question


Protocol is planned and specific

No protocol is included


Provides a summary of the available literature on the topic

Provides a summary of the available literature on the topic


Clear objectives are identified

Objectives may or may not be identified


Inclusion & exclusion criteria is stated before the review is started

Criteria is not specified

Search strategy

Comprehensive search conducted in a systematic way that can be repeated

Search strategy not explicitly stated

Selecting articles

Process stated explicitly

Not described in the literature review

Evaluating articles

Comprehensive evaluation of study quality included

Evaluation of study quality may or may not be included

Extracting relevant information

Process clearly stated

Not stated

Results and data synthesis

Clear summaries of studies based on high quality evidence

Summary based on studies where the quality of the articles may not be specified. May also be influenced by the reviewer's theories, needs and beliefs