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 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.
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