What is systematic review?
A systematic review is a critical assessment and evaluation of all research studies that address a particular clinical issue. The researchers use an organized method of locating, assembling, and evaluating a body of literature on a particular topic using a set of specific criteria. A systematic review typically includes a description of the findings of the collection of research studies. The systematic review may also include a quantitative pooling of data, called a meta-analysis. (Agency for Healthcare Research and Quality, Glossary of Terms, 2014)
The key characteristics of a systematic review are:
a clearly stated set of objectives with pre-defined eligibility criteria for studies;
an explicit, reproducible methodology;
a systematic search that attempts to identify all studies that would meet the eligibility criteria;
an assessment of the validity of the findings of the included studies, for example through the assessment of risk of bias; and
a systematic presentation, and synthesis, of the characteristics and findings of the included studies.
(Cochrane Handbook for Systematic Reviews of Interventions, 2008, p. 6)
Systematic reviews vs. Review articles: Similarities & Differences
|Systematic review||Literature review|
|Question||Focused on a single question.||Not necessarily focused on a single question, but may describe an overview.|
|Protocol||A peer review protocol or plan is included.||No protocol is included.|
|Background||Both provide summaries of the available literature on a topic|
|Objectives||Clear objectives are identified.||Objectives may or may not be identified.|
|Inclusion and exclusion criteria||Criteria stated before the review is conducted.||Criteria not specified.|
|Search strategy||Comprehensive search conducted in a systematic way.||Strategy 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.|
|Process of extracting relevant information||Usually clear and specific.||The process of extracting relevant information is not explicit and clear.|
|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.|
|Discussion||Written by an expert or group of experts with a detailed and well grounded knowledge of the issues.|
Reproduced from: Bettany-Saltikov, J. (2010). Learning how to undertake a systematic review: Part 1. Nursing Standard, 24(40): 47-55.