is a review of evidence-based studies and it aims to support the clinicians or researchers to find out the best available evidence to a specific problem
uses a rigorousresearch methodology to identify, select and appraise scholarly works in order to minimize bias
requires an exhaustive and reproducible search process
needs to include as many evidence as possible, both the positive and negative ones
A systematic review requires a systematic search and systematic organization of literature. Both the selection criteria (inclusion and exclusion) of articles and the search strategy need to be explicitly stated in the review with a predefined structure.
There is no place for an "unsystematic" review in health and social care research. Review in an unsystematic way may introduce biased results and can lead to misleading conclusions.
To understand the structure of systematic review, the most efficient way is to look at other systematic reviews in your research area. This process also helps you avoid duplication of effort. Visit Find Systematic Reviews to learn where to find published systematic reviews and propocols.
Systematic review may or may not include a meta-analysis, which is a quantitative summary of the results.
Here is a comparison of the two in detail:
Literature Review (or Narrative Review)
Research question is focusing on a single question.
Research question is not necessarily focusing on a single question, but may describe an overview.
A peer review protocol or plan is included.
No protocol is included.
Both provide summaries of the available literature on a topic.
Clear objectives are identified.
Objectives may or may not be identified.
Inclusion and exclusion criteria
Criteria is stated before the review is conducted.
Criteria is not specified.
Comprehensive search is conducted in a systematic way.
Strategy is not explicitly stated.
Process of selecting articles
Usually clear and explicit.
Not described in a literature review.
Process of evaluating articles
Comprehensive evaluation of study quality.
Evaluation of study quality may or may not be included.
Results and data synthesis
Clear summaries of studies based on high quality evidence.
Summary based on studies where the quality of articles may not be specified. May also be influenced by the reviewer’s theories, needs and beliefs.
Written by an expert or group of experts with a detailed and well grounded knowledge of the issues.