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Health Sciences Library

Systematic Literature Reviews: Types of Reviews

Information for those considering doing a systematic review.

So you want to do a systematic literature review...

In the 1990s, Evidence-Based Practice emerged as the new revolution in healthcare.  Healthcare workers wanted a way to know they were treating their patients with therapies that had been proven to work.   The literature at the time, however, did not offer such detailed, synthesized, categorized, non-biased information - and so the Systematic Literature Review was created.  The Cochrane Library was founded to advise, contain, curate, collect and offer access to these reviews.  Standards, guidelines and frameworks were developed by Cochrane and others in order to assure thoroughness, consistency and high quality. 

A systematic review requires a team effort, and many hours of work, starting with careful creation of a clinical question (PICO) that has not yet been answered in the literature and a protocol the team will use throughout the project to evaluate the articles.  Then a search of 3 or more databases, plus 'gray literature', preferably including foreign language articles, often gathering hundreds (sometimes thousands) of articles.  The next steps would be: reading, evaluating, sorting the articles and deciding which should be included or excluded.  Every step needs to be meticulously documented and analyzed according to the protocol, since a systematic review is meant to be totally reproducible by other scholars and researchers.  That is a huge amount of work.  Are you ready to do that? If so, great!!  If you are hesitant, maybe read on for more information, maybe another type of review is more appropriate to your question.

Here's a video to help explain it better.

Organizational Tools

One (very important) aspect of Systematic Literature Reviews is to make them reproducible.  Your work needs to be transparent, and fully recorded, so that another person doing the research will gather the exact same results.  Here are some tools that make organizing your information easier.  Except for EndNote, the Rowan-Virtua SOM Librarians won't be able to answer technical questions on these packages.  

Types of Reviews

There are many types of reviews, here are some very short explanations of the more popular ones. Please see this article for more information.

  • Systematic Review - Systematic reviews, as the name implies, typically involve a detailed and comprehensive plan and search strategy derived a priori, with the goal of reducing bias by identifying, appraising, and synthesizing all relevant studies on a particular topic. Often, systematic reviews include a meta-analysis component which involves using statistical techniques to synthesize the data from several studies into a single quantitative estimate or summary effect size.  Read more. Example.
     

  • Scoping Review - The purpose of a scoping review is to provide an overview of the available research evidence without producing a summary answer to a discrete research question. Scoping reviews can be useful for answering broad questions, such as “What information has been presented on this topic in the literature?” and for gathering and assessing information prior to conducting a systematic review.  Read more.   Example.

  • State of the Art Review - A state-of-the-art review considers mainly the most current research in a given area or concerning a given topic. It often summarizes current and emerging educational trends, research priorities and standardisations in a particular field of interest. The review aims to provide a critical survey of the extensive literature produced in the past decade, a synthesis of current thinking in the field. It may offer new perspectives on an issue or point out an area in need of further research.  Read more. Example.

  • Rapid Review - Rapid reviews are a form of knowledge synthesis in which components of the systematic review process are simplified or omitted to produce information in a timely manner.   Read more. Example.

  • Umbrella Review - Syntheses of existing systematic reviews are referred to by many different names, one of which is an umbrella review. An umbrella review allows the findings of reviews relevant to a review question to be compared and contrasted. An umbrella review's most characteristic feature is that this type of evidence synthesis only considers for inclusion the highest level of evidence, namely other systematic reviews and meta-analyses. Read more.  Example.

  • Overview of Reviews - Cochrane Overviews of Reviews (Cochrane Overviews) use explicit and systematic methods to search for and identify multiple systematic reviews on related research questions in the same topic area for the purpose of extracting and analysing their results across important outcomes. Read more.  Example. 

  • Meta-analysis - Meta-analysis is the statistical procedure for combining data from multiple studies. When the treatment effect (or effect size) is consistent from one study to the next, meta-analysis can be used to identify this common effect. When the effect varies from one study to the next, meta-analysis may be used to identify the reason for the variation. Read more.  Example.

  • Mapping Review - A review that seeks to identify, not results, but linkages. Mapping focuses on characteristics such as where the activity took place, where the funding came from, and in what journal or other medium it was presented. Mapping often focuses on published items but need not; some mapping studies include other media (e.g., books, newspapers, grant proposals). Read more. Example. 

  • Literature Review - A literature review helps any researchers by providing context, informing methodology, identifying innovation, minimizing duplicative research, and ensuring that professional standards are met. Read more. Example. 

  • Narrative Review - Narrative reviews tend to be mainly descriptive, do not involve a systematic search of the literature, and thereby often focus on a subset of studies in an area chosen based on availability or author selection. Thus narrative reviews while informative, can often include an element of selection bias.  Read more.  Example. 

  • Original Research/Journal Article -   This is the most common type of journal manuscript used to publish full reports of data from research. It may be called an Original Article, Research Article, Research, or just Article, depending on the journal. The Original Research format is suitable for many different fields and different types of studies. It includes full Introduction, Methods, Results, and Discussion sections.  Read more.   Example.

Databases

PubMed and Embase are two databases that should always be searched.  Choose other databases based on their subject strength.  Find more databases at the library website, under "Medical Resources".