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
- A 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).
- Health technology assessments involve "the systematic evaluation of the properties and effects of a health technology, addressing the direct and intended effects of this technology, as well as its indirect and unintended consequences, and aimed mainly at informing decision making regarding health technologies" (Health Technology Assessment International, glossary). "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 these assessments.
- 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 (see this interactive infographic).
- 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 .
- 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) the most widely used guide, but also Pham et al (2014) which tries to clarify the definition.
- 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.