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Systematic Reviews and Searching the Literature

Resources and tips when preparing a systematic review or other reports that require a thorough search of the literature. Updated Aug 19, 2020.


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There are several types of documents that require a thorough search of the healthcare literature :

  • A systematic review is a "high-level overview of primary research on a particular research question that tries to identify, select, synthesize and appraise all high quality research evidence relevant to that question in order to answer it" (Cochrane Collaboration). Key characteristics include:
    • collation of all evidence that fits pre-specified eligibility criteria in order to address a specific research question
    • minimization of bias by using explicit, systematic methods
  • stack of papersA meta-analysis is a type of review that statistically combines data of individual studies leading to more powerful analyses and potentially more sweeping conclusions (Cochrane Collaboration).
  • The term, scoping review,  is used variably by review authors but they tend to have in common the goal of "mapping" a topic with limited critical appraisal of the included studies.  The scoping review in approach is similar to a systematic review (thorough search of the literature, careful consideration of inclusion/exclusion criteria) but may not necessarily exclude studies that lack methodological rigor.  For more on scoping reviews see Arksey and O'Malley (2005) and Pham et al (2014). Also see the handbook at Joanna Briggs Institute (2017) on how to conduct scoping reviews and PRISMA-ScR (2018) on what to report.
  • Health technology assessments involve "...refers to the the systematic evaluation of properties, effects, and/or impacts of health technology. It is a multidisciplinary process to evaluate the social, economic, organizational and ethical issues of a health intervention or health technology. The main purpose of conducting an assessment is to inform a policy decision making." (World Health Organization, Health Products Policy and Standards). "Health technologies can include pharmaceuticals, devices, diagnostics and treatments, and other clinical, public health, and organizational interventions" (Health Technology Assessment International). Cost analysis is often an important part HTAs and is generally meant to inform health policy.
  • Practice guidelines consist of "a set of directions or principles to assist the health care practitioner with patient care decisions about appropriate diagnostic, therapeutic, or other clinical procedures for specific clinical circumstances" (NLM PubMed MeSH database).  Clinical practice guidelines "are statements that include recommendations intended to optimize patient care that are informed by a systematic review of evidence and an assessment of the benefits and harms of alternative care options" ("Clinical Practice Guidelines We Can Trust", Institute of Medicine). Systematic reviews help inform the development of clinical practice guidelines.
  • The integrative research review may have similar goals as the systematic review in comprehensively gathering the best evidence but unlike the systematic review the integrative review method "...allows for the inclusion of diverse methodologies (i.e. experimental and non-experimental research) ..." and may have wide-ranging purposes such as "to define concepts, to review theories, to review evidence, and to analyse methodological issues of a particular topic" (Whittmore and Knafl, 2005). The integrative review may be more suited for disciplines such as nursing, that rely extensively on qualitative data .
  • An umbrella review synthesizes evidence in systematic reviews or meta-analyses.  They have been referred to as "systematic reviews of systematic reviews."  Aromataris et al. (2015)  recently published guidelines on conducting and reporting umbrella reviews, the Joanna Briggs Institute handbook (2017) on umbrella reviews.