A systematic review is a summary of all the best available research on a specific question, using transparent replicable protocols to find, evaluate and synthesize relevant research evidence. Protocols are defined in advance in order to minimize bias and reviewers screen the located evidence for quality. All relevant research evidence is aggregated and evaluated to generate an evidence synthesis. A systematic review may include a meta-analysis where quantitative evidence is sufficiently homogenous. This short video provides a brief introduction on the purpose and processes related to a systematic review.
Be clear in regard to the type of literature review required for your research inquiry. Systematic reviews are resource intensive. They require detailed, comprehensive plans and search with the goal of synthesizing all relevant studies on a particular topic. Alternatively, narrative literature reviews are critical and interpretive summaries. This table lists the differences.
|Systematic Literature Review||Narrative Literature Review|
|Definition||High level overview of research on a focused question that identifies, selects, synthesizes and appraises all high quality research evidence relevant to that question.||Qualitatively summarizes evidence on a topic using informal or subjective methods to collect and interpret studies.|
|Goals||Answer a focused clinical question. Eliminates bias.
||Provide a summary/overview of a topic.|
|Question||Clearly defined & answerable clinical question.||Can be a general topic or a specific question.|
|Components||Registered protocol with pre-specified eligibility criteria.
Systematic & replicable search strategy.
Assessment of the validity of findings.
Interpretation and presentation of results.
|No. of Authors||At least 2 for a formal systematic review to eliminate bias.||1 or more.|
|Timeline||6 to 12 months, average 12 months.
See Timeline for a Cochrane review
|Weeks to months.|
|Requirements||Thorough knowledge of topic.
Performs searches of all relevant databases.
Statistical analysis resources (for meta-analysis).
|Understanding of topic.
Performs searches of one or more databases.
|Value||Connects practicing clinicians to high quality evidence.
Supports evidence based practice.
|Provides summary of literature on a topic.|
Source: Kysh, L.. (2013). Difference between a systematic review and a literature review (Version 1). figshare. doi:10.6084/m9.figshare.766364.
Unal, E., Giakoumidakis, K., Khan, E., & Patelarou, E. (2018). Mobile phone text messaging for improving secondary prevention in cardiovascular diseases: A systematic review. Heart & Lung, 47(4), 351-359.doi: https://doi.org/10.1016/j.hrtlng.2018.05.009
Von Philipsborn P, Stratil JM, Burns J, Busert LK, Pfadenhauer LM, Polus S, Holzapfel C, Hauner H, Rehfuess E. Environmental interventions to reduce the consumption of sugar‐sweetened beverages and their effects on health. Cochrane Database of Systematic Reviews 2019, Issue 6. Art. No.: CD012292. DOI: 10.1002/14651858.CD012292.pub2.