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:
A systematic review can be either quantitative or qualitative.
A systematic review involves the following steps:
This table outlines the differences between a systematic review and a literature review:
Systematic Review | Literature Review | |
Question | Focused on a single question | Not necessarily focused on a single question, but may describe an overview |
Protocol | Includes a peer review protocol or plan | No protocol is included |
Background | Provides summaries of the available literature on a topic | Provides summaries of the available literature on a topic |
Objectives | Clear objectives are identified | Objectives may or may not be identified |
Inclusion/exclusion criteria | Criteria is stated before review is conducted | Criteria is not specified |
Search strategy | Comprehensive search conducted in a systematic way | Strategy not explicitly stated |
Process of selecting articles | Process 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 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 |
Discussion | Written by an expert or group of experts with a detailed and well grounded knowledge of the issues | Written by an expert or group of experts with a well grounded knowledge of the issues |
Adapted from: University of Newcastle Australia Library
Systematic Review | Scoping Review | |
What is it? | Attempts to identify, appraise and synthesize all empirical evidence that meets pre-specified eligibility criteria to answer a given research question | A rapid gathering of literature in a given area, aiming to provide an overview of the type, extent and quantity of research available |
Why choose this method? | To address a clearly focused review question by finding the best available, relevant studies and synthesizing the results | To capture the breadth of literature; identify gaps in a research area; occasionally used as a precursor to a systematic review |
Question | Focused research question with narrow parameters | The research question is often broad |
Eligibility criteria | Inclusion/exclusion usually defined at outset | Inclusion/exclusion can be developed post hoc |
Appraisal | Rigorous critical appraisal and evaluation of study quality | Appraisal can be variable; typically not done, or may be done in a narrative form |
Synthesis | Clear summaries of studies based on high quality evidence. May include a meta-analysis | The summary is usually descriptive |
Inferences | Evidence based | Evidence based |
Adapted from: University of South Australia
A useful article:
Munn, Z., Peters, M. D. J., Stern, C., Tufanaru, C., McArthur, A., & Aromataris, E. (2018). Systematic review or scoping review? Guidance for authors when choosing between a systematic or scoping review approach. BMC Medical Research Methodology, 18(1), 143. https://doi.org/10.1186/s12874-018-0611-x
"Rapid reviews have emerged as a streamlined approach to synthesizing evidence-typically for informing emergent decisions faced by decision makers in health care setting".
Systematic Review | Rapid Review | |
Question | Often a focused clinical question (focused PICOS) | Narrow question (may use PICOS) |
Sources and searches | Comprehensive sources searched and explicit strategies | Sources may be limited but sources and strategies made explicit |
Selection | Criterion-based | Criterion-based; uniformly applied |
Appraisal | Rigorous; critical appraisal | Rigorous, critical appraisal (SRs only) |
Synthesis | Qualitative summary with/without meta-analysis | Descriptive summary/categorisation of data |
Inferences | Evidence-based |
Limited/cautious interpretation of findings |
Source: Khangura, S., Konyu, K., Cushman, R., Grimshaw, J. & Moher, D. (2012). Evidence summaries: the evolution of a rapid review approach. Sytematic Review, 1-10. https://doi.org/10.1186/2046-4053-1-10
Examples of different types of reviews:
Systematic review:
Barriers and facilitators to health screening in men: A systematic review
https://doi.org/10.1016/j.socscimed.2016.07.023
Literature review:
A Literature review of mentorship programs in academic nursing
https://doi.org/10.1016/j.profnurs.2017.02.007
Scoping review:
How do patients experiecne caring? Scoping review
https://doi.org/10.1016/j.pec.2017.03.029
Rapid review:
Blended foods for tube-fed children: a safe and realistic option? A rapid review of the evidence
https://doi.org/10.1136/archdischild-2016-311030