Literature Reviews

Definition:

"An assessment of what is already known about a policy or practice issue...using systematic review methods to search and critically appraise existing research" (Grant & Booth, 2009, p. 100).

Characteristics:

• Assessment of what is already known about an issue
• Similar to a systematic review but within a time-constrained setting
• Typically employs methodological shortcuts, increasing risk of introducing bias, includes basic level of quality assessment
• Best suited for issues needing quick decisions and solutions (i.e., policy recommendations)

Learn more about the method:

Khangura, S., Konnyu, K., Cushman, R., Grimshaw, J., & Moher, D. (2012). Evidence summaries: the evolution of a rapid review approach. Systematic reviews, 1(1), 1-9. https://doi.org/10.1186/2046-4053-1-10

Virginia Commonwealth University Libraries. (2021). Rapid Review Protocol.

Example:

Quarmby, S., Santos, G., & Mathias, M. (2019). Air quality strategies and technologies: A rapid review of the international evidence. Sustainability, 11(10), 2757. https://doi.org/10.3390/su11102757

Grant, M.J. & Booth, A. (2009). A typology of reviews: an analysis of the 14 review types and associated methodologies. Health Information & Libraries Journal, 26(2), 91-108. https://www.doi.org/10.1111/j.1471-1842.2009.00848.x

Definition:

Developed and refined by the Evidence for Policy and Practice Information and Co-ordinating Centre (EPPI-Centre), this review "map[s] out and categorize[s] existing literature on a particular topic, identifying gaps in research literature from which to commission further reviews and/or primary research" (Grant & Booth, 2009, p. 97).

Characteristics:

• Although mapping reviews are sometimes called scoping reviews, the key difference is that mapping reviews focus on a review question, rather than a topic

• Mapping reviews are "best used where a clear target for a more focused evidence product has not yet been identified" (Booth, 2016, p. 14)

• Mapping review searches are often quick and are intended to provide a broad overview

• Mapping reviews can take different approaches in what types of literature is focused on in the search

Learn more about the method:

Cooper I. D. (2016). What is a "mapping study?". Journal of the Medical Library Association: JMLA, 104(1), 76–78. https://doi.org/10.3163/1536-5050.104.1.013

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(1), 1-21. https://doi.org/10.1186/s13643-016-0204-x

Example:

Tainio, M., Andersen, Z. J., Nieuwenhuijsen, M. J., Hu, L., De Nazelle, A., An, R., ... & de Sá, T. H. (2021). Air pollution, physical activity and health: A mapping review of the evidence. Environment international, 147, 105954. https://doi.org/10.1016/j.envint.2020.105954

Booth, A. (2016). EVIDENT Guidance for Reviewing the Evidence: a compendium of methodological literature and websites. ResearchGate. https://doi.org/10.13140/RG.2.1.1562.9842. 

Grant, M.J. & Booth, A. (2009). A typology of reviews: an analysis of the 14 review types and associated methodologies. Health Information & Libraries Journal, 26(2), 91-108. https://www.doi.org/10.1111/j.1471-1842.2009.00848.x

Definition:

"A type of review that has as its primary objective the identification of the size and quality of research in a topic area in order to inform subsequent review" (Booth et al., 2012, p. 269).

Characteristics:

• Main purpose is to map out and categorize existing literature, identify gaps in literature—great for informing policy-making
• Search comprehensiveness determined by time/scope constraints, could take longer than a systematic review
• No formal quality assessment or critical appraisal

Learn more about the methods:

Arksey, H., & O'Malley, L. (2005) Scoping studies: towards a methodological framework. International Journal of Social Research Methodology, 8(1), 19-32. https://doi.org/10.1080/1364557032000119616

Levac, D., Colquhoun, H., & O’Brien, K. K. (2010). Scoping studies: Advancing the methodology. Implementation Science: IS, 5, 69. https://doi.org/10.1186/1748-5908-5-69

Example: 

Rahman, A., Sarkar, A., Yadav, O. P., Achari, G., & Slobodnik, J. (2021). Potential human health risks due to environmental exposure to nano-and microplastics and knowledge gaps: A scoping review. Science of the Total Environment, 757, 143872. https://doi.org/10.1016/j.scitotenv.2020.143872

Booth, A., Papaioannou, D., & Sutton, A. (2012). Systematic approaches to a successful literature review. London: SAGE Publications Ltd.

Definition:

A review that "[compiles] evidence from multiple...reviews into one accessible and usable document" (Grant & Booth, 2009, p. 103). While originally intended to be a compilation of Cochrane reviews, it now generally refers to any kind of evidence synthesis.

Characteristics:

• Compiles evidence from multiple reviews into one document
• Often defines a broader question than is typical of a traditional systematic review

Learn more about the method:

Choi, G. J., & Kang, H. (2022). The umbrella review: a useful strategy in the rain of evidence. The Korean Journal of Pain, 35(2), 127–128. https://doi.org/10.3344/kjp.2022.35.2.127

Aromataris, E., Fernandez, R., Godfrey, C. M., Holly, C., Khalil, H., & Tungpunkom, P. (2015). Summarizing systematic reviews: Methodological development, conduct and reporting of an umbrella review approach. International Journal of Evidence-Based Healthcare, 13(3), 132–140. https://doi.org/10.1097/XEB.0000000000000055

Example:

Rojas-Rueda, D., Morales-Zamora, E., Alsufyani, W. A., Herbst, C. H., Al Balawi, S. M., Alsukait, R., & Alomran, M. (2021). Environmental risk factors and health: An umbrella review of meta-analyses. International Journal of Environmental Research and Public Dealth, 18(2), 704. https://doi.org/10.3390/ijerph18020704

Grant, M.J. & Booth, A. (2009). A typology of reviews: an analysis of the 14 review types and associated methodologies. Health Information & Libraries Journal, 26(2), 91-108. https://www.doi.org/10.1111/j.1471-1842.2009.00848.x

Definition:

A meta-analysis is a "technique that statistically combines the results of quantitative studies to provide a more precise effect of the result" (Grant & Booth, 2009, p. 98).

Characteristics:

• Statistical technique for combining results of quantitative studies to provide more precise effect of results
• Aims for exhaustive, comprehensive searching
• Quality assessment may determine inclusion/exclusion criteria
• May be conducted independently or as part of a systematic review

Learn more about the method:

Berman, N. G., & Parker, R. A. (2002). Meta-analysis: Neither quick nor easy. BMC Medical Research Methodology, 2(1), 10. https://doi.org/10.1186/1471-2288-2-10

Example:

Hites R. A. (2004). Polybrominated diphenyl ethers in the environment and in people: a meta-analysis of concentrations. Environmental Science & Technology, 38(4), 945–956. https://doi.org/10.1021/es035082g

Grant, M.J. & Booth, A. (2009). A typology of reviews: an analysis of the 14 review types and associated methodologies. Health Information & Libraries Journal, 26(2), 91-108. https://www.doi.org/10.1111/j.1471-1842.2009.00848.x

Definition:

A systematic review "seeks to systematically search for, appraise, and [synthesize] research evidence, often adhering to the guidelines on the conduct of a review" provided by discipline-specific organizations, such as the Cochrane Collaboration (Grant & Booth, 2009, p. 102).

Characteristics:

• Aims to compile and synthesize all known knowledge on a given topic
• Adheres to strict guidelines, protocols, and frameworks
• Time-intensive and often takes months to a year or more to complete
• The most commonly referred to type of evidence synthesis. Sometimes confused as a blanket term for other types of reviews

Example:

Gascon, M., Triguero-Mas, M., Martínez, D., Dadvand, P., Forns, J., Plasència, A., & Nieuwenhuijsen, M. J. (2015). Mental health benefits of long-term exposure to residential green and blue spaces: a systematic review. International Journal of Environmental Research and Public Health, 12(4), 4354–4379. https://doi.org/10.3390/ijerph120404354

Grant, M.J. & Booth, A. (2009). A typology of reviews: an analysis of the 14 review types and associated methodologies. Health Information & Libraries Journal, 26(2), 91-108. https://www.doi.org/10.1111/j.1471-1842.2009.00848.x

Definition:

"Systematized reviews attempt to include one or more elements of the systematic review process while stopping short of claiming that the resultant output is a systematic review" (Grant & Booth, 2009, p. 102). When a systematic review approach is adapted to produce a more manageable scope, while still retaining the rigor of a systematic review such as risk of bias assessment and the use of a protocol, this is often referred to as a structured review (Huelin et al., 2015).

Characteristics:

• Typically conducted by postgraduate or graduate students
• Often assigned by instructors to students who don't have the resources to conduct a full systematic review

Example:

Salvo, G., Lashewicz, B. M., Doyle-Baker, P. K., & McCormack, G. R. (2018). Neighbourhood built environment influences on physical activity among adults: A systematized review of qualitative evidence. International Journal of Environmental Research and Public Health, 15(5), 897. https://doi.org/10.3390/ijerph15050897

Grant, M.J. & Booth, A. (2009). A typology of reviews: an analysis of the 14 review types and associated methodologies. Health Information & Libraries Journal, 26(2), 91-108. https://www.doi.org/10.1111/j.1471-1842.2009.00848.x

Huelin, R., Iheanacho, I., Payne, K., & Sandman, K. (2015). What’s in a name? Systematic and non-systematic literature reviews, and why the distinction matters. https://www.evidera.com/resource/whats-in-a-name-systematic-and-non-systematic-literature-reviews-and-why-the-distinction-matters/