A systematic review is a summary of the medical literature that uses explicit methods to perform a comprehensive literature search and critical appraisal of individual studies and that uses appropriate statistical techniques to combine these valid studies. (CEBM).
Key characteristics of a systematic review are:
Meta-analysis is a systematic review process that uses quantitative methods to synthesize and summarize the results.
Meta-synthesis is a systematic review process that synthesises a number of qualitative studies to reveal new understandings
Shamseer, L., & Moher, D. (2015). Planning a systematic review? Think protocols. Retrieved from BioMed Central blog:https://blogs.biomedcentral.com/bmcblog/2015/01/05/planning-a-systematic-review-think-protocols/
The Equator Network develops and provides Reporting Guidelines for all types of studies
Scoping review – an overview of a broad field; can show research gaps. Can be an ideal first review for any research project.
Read this excellent overview
Peters, M. D., Godfrey, C. M., Khalil, H., McInerney, P., Parker, D., & Soares, C. B. (2015). Guidance for conducting systematic scoping reviews. International Journal of Evidence-Based Healthcare, 13(3), 141-146. doi:10.1097/XEB.0000000000000050
Tricco, A. C., Lillie, E., Zarin, W., O'Brien, K., Colquhoun, H., Kastner, M., . . . Straus, S. E. (2016). A scoping review on the conduct and reporting of scoping reviews. BMC Medical Research Methodology, 16, 15. doi:10.1186/s12874-016-0116-4
Colquhoun, H. (2016 May). Current best practice for the conduct of scoping reviews, (Powerpoint slides) Presented at Impactful Biomedical Research: Achieving Quality and Transparency. Available from: http://www.equator-network.org/wp-content/uploads/2016/06/Gerstein-Library-scoping-reviews_May-12.pdf
Arksey, H., & O'Malley, L. (2005). Scoping studies: Towards a methodological framework. International Journal of Social Research Methodology, 8(1), 19-32. doi:10.1080/1364557032000119616
[Reporting Guideline PRISMA-ScR is currently under development by the Equator Network (2017)].
Protocol – a stated intention to perform a review; detailing purpose, methods, search strategies, databases and exclusion criteria.
Register the protocol with PROSPERO https://www.crd.york.ac.uk/PROSPERO/
Use PRISMA-P guidelines to develop the protocol
Shamseer, L., Moher, D., Clarke, M., Ghersi, D., Liberati, A., Petticrew, M., . . . Group, P.-P. (2015). Preferred reporting items for systematic review and meta-analysis protocols (PRISMA-P) 2015: elaboration and explanation. BMJ, 349, g7647. doi:10.1136/bmj.g7647
Rapid review – when there is not the time to execute a full SR; but without compromising quality
Beware of methodology issues...
Tricco, A. C., Antony, J., Zarin, W., Strifler, L., Ghassemi, M., Ivory, J., . . . Straus, S. E. (2015). A scoping review of rapid review methods. BMC Medicine, 13, 224. doi:10.1186/s12916-015-0465-6
Schünemann, H. J., & Moja, L. (2015). Reviews: Rapid! Rapid! Rapid! …and systematic. Systematic Reviews, 4(1), 4. doi:10.1186/2046-4053-4-4
Evidence map – a visual summation of existing evidence
Miake-Lye, I. M., Hempel, S., Shanman, R., & Shekelle, P. G. (2016). What is an evidence map? A systematic review of published evidence maps and their definitions, methods, and products. Systematic Reviews, 5, 28. doi:10.1186/s13643-016-0204-x
Example based on an SR of SRs
Solloway, M. R., Taylor, S. L., Shekelle, P. G., Miake-Lye, I. M., Beroes, J. M., Shanman, R. M., & Hempel, S. (2016). An evidence map of the effect of Tai Chi on health outcomes. Systematic Reviews, 5(1), 126. doi:10.1186/s13643-016-0300-y
Realist review – how and why complex social interventions work
Gough, D. (2013). Meta-narrative and realist reviews: guidance, rules, publication standards and quality appraisal. BMC Medicine, 11, 22. doi:10.1186/1741-7015-11-22
Pawson, R., Greenhalgh, T., Harvey, G., & Walshe, K. (2005). Realist review - A new method of systematic review designed for complex policy interventions. Journal of Health Services Research and Policy, 10(SUPPL. 1), 21-34. doi:10.1258/1355819054308530
Note: There are many other types of review. Those above and others are identified and discussed here:
Grant, M. J., & Booth, A. (2009). A typology of reviews: an analysis of 14 review types and associated methodologies. Health Information and Libraries Journal 26(2), 91-108. doi:10.1111/j.1471-1842.2009.00848.x
Reproduced from: Bettany-Saltikov, J. (2010). Learning how to undertake a systematic review: Part 1. Nursing Standard, 24(40): 47-55.
|Systematic Review||Narrative 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||Not clear or explicit|
|Results and Data Synthesis||Clear summaries of studies 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|
Saltikov, J., & Fernandes, T. (2010). Learning how to undertake a systematic review: Part 1. Nursing Standard, 24(50), 47-55; quiz 56. Retrieved from http://ezproxy.usc.edu.au:2048/login?url=http://search.proquest.com/docview/751264535?accountid=28745
Bettany-Saltikov, J. (2010). Learning how to undertake a systematic review: Part 2. Nursing Standard, 24(51), 47-56; quiz 58, 60. Retrieved from http://ezproxy.usc.edu.au:2048/login?url=http://search.proquest.com/docview/751267350?accountid=28745
Saltman,D., Jackson,D., Newton, P.J. & Davidson, P.M. (2013). In pursuit of certainty: Can the systematic review process deliver? BMC Medical Informatics and Decision Making, 13, 25. doi:10.1186/1472-6947-13-25
Petticrew, M. (2009). Systematic reviews in public health: Old chestnuts and new challenges [Editorial]. Bulletin of the World Health Organization, 87(3), 163. doi: 10.2471/BLT.09.063719 . Retrieved from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2654648/ (Good argument for the role of SRs where there is no single clinical question).