Glossary

Evidence searching and national guidance

The glossary of terms for the national searching guidance

(££)

When this appears after a resource in this guidance it means that it requires a paid subscription, and is neither included within the national core content collection nor freely available.

Artificial Intelligence (AI)

A broad umbrella term referring to technology that essentially mimics human thought processes, incorporating generative artificial intelligence, large language models and other machine learning technologies utilised by AI tools such as ChatGPT and Perplexity.

For further definitions see Defining artificial intelligence for librarians, published in Journal of Librarianship and Information Science in 2022.

Audit

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An audit is an official internal or external examination of an organisation… Clinical audit is a tool for improving practice, patient care or services provided. It is used to measure current practice and care against a set of explicit standards or criteria, identify areas for improvement, make changes to practice and re-audit to ensure that improvement has been achieved. The findings of the clinical audit provide evidence of the quality of practice and care.
NHS Digital - glossary. See also: Healthcare Quality Improvement Partnership's (HQIPs) “Clinical Audit: A Manual for Lay Members of the Clinical Audit Team” by Margaret Hughes BSc (Hons) (2012).

Business case

Usually involves a bid for funding and/or additional staffing.

What is a business case?

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A proposal for a strategy or course of action. It can be considered a pitch that gives stakeholders the information they need to make a decision to invest in a project.
Simplicable: What is a business case?

Citation index

A database, such as Scopus, (££) that allows you to perform citation searches to see what research a paper has cited, and what research it has subsequently been cited by. For guidance on conducting and reporting citation searches, please see the University of Basel's Terminology, Application, and Reporting of Citation Searching (TARCiS statement.

Clinical decision support (CDS) tool

App and/or website designed for referral by clinicians at the pointof-care. Organised encyclopaedically, it contains high-tier evidence that summarises the best available evidence on conditions/interventions. Examples include:

  • British Medical Journal (BMJ) Best Practice (freely available to all NHS staff)
  • DynaMed (££)
  • UpToDate (££)
  • Visual Dx (££)

Clinical trial registers/clinical trials registry

These databases contain records of clinical trials that are inprogress, the results of which may not be published for a long time. For example, the Clinical Trials website.

Commissioning

What is commissioning?

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The continual process of planning, agreeing and monitoring services. Commissioning is not one action but many, ranging from the health-needs assessment for a population, through the clinically based design of patient pathways, to service specification and contract negotiation or procurement, with continuous quality assessment.
NHS England: What is commissioning? 

Evidence search tracking system

An online or local platform that a library service uses to log evidence search requests from users, build evidence search reports, and store complete evidence search reports for future reference. KnowledgeShare and CISS are 2 examples. See Sarah Rudd and others “Evidence Searching Process Map” (link to be added shortly).

Filter

What is a search filter or hedge?

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Search filters or hedges are search strategies that include a series of pre-elaborated free text terms/text words/phrases and subject headings for a given concept, idea, or study design.
University of California, Los Angeles (UCLA) Library: What is a search filter or hedge?

Grey literature

Looking beyond bibliographic databases for grey literature is important when searching for evidence around health inequalities, owing to the under-representation of some populations in the literature.

NICE - Glossary

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Literature that is not formally published or that has a limited distribution, such as institutional reports. Grey literature may not be easily identified through standard bibliographic retrieval systems.
National Institute for Health and Care Excellence (NICE): Glossary

Health inequalities

What are health inequalities?

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Avoidable, unfair and systematic differences in health between different groups of people… In England, health inequalities are often analysed and addressed by policy across four types of factors: socio-economic factors, for example, income; geography, for example, region or whether urban or rural; specific characteristics including those protected in law, such as sex, ethnicity or disability; socially excluded groups, for example, people experiencing homelessness. People experience different combinations of these factors, which has implications for the health inequalities that they are likely to experience.
King's Fund: What are health inequalities?

High tier evidence

Evidence such as national/international guidance, systematic reviews and meta-analyses from the top tiers of the “pyramid of evidence” that collates and reports on the findings of primary research. Find the evidence pyramid image on Wikipedia Commons.

See also the new evidence Pyramid published in BMJ Evidence Based Medicine. This covers sources that index and appraise this evidence, like the Cochrane Library, the Campbell Collaboration website, and the Joanna Briggs Institute’s website.

Lower tier evidence/primary research

Individual studies of various methodologies from the bottom tier(s) of the “pyramid of evidence”, that investigate a specific healthcare question.

PICO

A model or framework for structuring a research question or search strategy.

  • P = Population/Patient
  • I = Intervention
  • C = Comparison/Control
  • O = Outcome.

Other models can be used and may be more useful for specific types of questions.

Preprint server/pre-publication database

Platforms such as medRxiv that provide free access to the full text of manuscripts (author drafts) of research that have been submitted for publication in a journal. These typically contain the papers before they are peer-reviewed, and may differ significantly from the final published version, so advise a requester of this if you include them in your results.

Quality improvement (QI)

A very popular methodology within the NHS, with many organisations having dedicated QI departments.

Making the case for quality improvement

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The use of methods and tools to continuously improve quality of care and outcomes for patients.
King's Fund: Making the case for quality improvement

Scoping search

An initial quick search to get an idea of what is available on your search topic. Typically very specific, not comprehensive, a first step in a more exhaustive systematic search for evidence. Not to be confused with "scoping review".

Source: Meeting the review family: exploring review types and associated information retrieval requirements.

Search strategy/search history

Search strategy

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Series of command expressions intended to satisfy a request for information. A search strategy may include a variety of database selection commands, term identification commands and search and display commands.
International Standards Organization Information and Documentation: Search strategy

Subject heading

While subject headings are descriptors, subheadings are qualifiers of those, letting you choose specific aspects on your search topic. There are 83 subheadings in MeSH, not all can be used with all subject headings (the available subheadings are described in the scope note of selected subject heading).

Online Dictionary for Library and Information Science (ODLIS)

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The most specific word or phrase that describes the subject, or one of the subjects, of a work, selected from a list of preferred terms (controlled vocabulary) and assigned as an added entry in the bibliographic record to serve as an access point (in a database or library catalogue).

A subject heading may be subdivided by the addition of subheadings.
Reitz JM Online Dictionary for Library and Information Science: Glossary

Floating subject headings

These can be used when a particular subheading you want to apply is not presented as an option to combine with a subject heading. For example, when searching Medline via Ovid, to find research on surgical trends in brain cancer using MeSH terms, you can enter the command “BRAIN NEOPLASMS/ AND td.fs”: “td” is the abbreviation for the “trends” subheading, and “fs” is the abbreviation for the floating subheading index.

Floating subject headings can also be searched, and these retrieve anything that uses that subheading, irrespective of which subject heading it is assigned to.

Note: floating only works in the Ovid provider interface.

Summarising

Briefly outlining the contents and important points of a document/report.  See the Learning Zone's Synthesising and Summarising section for a further definition and hoe it differs from synthesising.

Synthesising

Combining the conclusions or findings of several sources into a single report, contextualising them.

Source: Literature Search Standards Working Group: Glossary

Further glossaries

Page last reviewed: 12 March 2026
Next review due: 12 March 2028