LibGuides: Searching: Search Filters

What are Filters?

Filters (also called hedges) are used to narrow a search and/or focus in on a specific publication type, level of evidence, and/or subject area. Filters are constructed using specific database syntax (rules and commands). Strategies are developed with rules and commands used to search a variety of databases and interfaces including PubMed, Ovid, Embase, and CINAHL. Some filters are adjusted to be more sensitive (accurate identification) or specific (accurate exclusion).

Several research and healthcare groups produce pre-tested strategies that identify high quality evidence or focus in on a particular health care field or area. Using pre-existing filters or strategies can assist in managing the vast amounts of literature indexed in the major medical databases, and provide you with a smaller number of articles to start with when searching.

When using pre-existing filters be mindful of:

Authority of filter or strategy creator
Specificity versus sensitivity of results
Syntax of filter and what database it was developed for.

While it is important to be aware of the authority and accuracy of a specific filter, using a filter that has not been validated or tested is not incorrect. It is important to recognize and identify the impact that using a particular filter may have on your search results. If a particular filter works well in a given context and does not appear to be producing a high number of irrelevant results or excluding relevant items, by all means use that filter.

Study Type / Level of Evidence / Question

Several trusted groups have developed filters to narrow search results by methodology, publication type or question category (therapy, diagnosis, etiology, prognosis, clinical prediction guides).

The InterTASC Information Specialists' Sub-Group Search Filter Resource
The InterTASC Information Specialists' Sub-Group Search Filter Resource identifies, assesses and tests search filters designed to retrieve research by study design or focus. This resource provides access to both published and unpublished search filters.
McMaster Health Knowledge Refinary Hedges
Use these filters developed by McMaster University's Health Information Research Unit to narrow search results in Medline, Embase, and PsycINFO according to category (therapy, diagnosis, prognosis, reviews, clinical prediction guides, quality improvement, qualitative studies, causation (etiology), costs, economics). Medline filters in Ovid and PubMed syntax. Embase and PsycINFO in Ovid syntax.
SIGN Methodology Filters
Search filters developed by SIGN for Systematic Reviews, Randomized Control Trials, Observational Studies, Diagnostic Studies, Economic Studies, Patent Issues. All filters in Ovid syntax.
BMJ Best Practice: Study Design Search Filters
Systematic review, Randomized control trial, Cohort study, Cohort & case control, Adverse effects, and other strategies for Medline and Embase (OVID online search interface).
Search Filters Database - Canada's Drug Agency (formerly called CADTH)
Filters for systematic reviews, health technology assessments, randomized controlled trials and guidelines in PubMed, Ovid Medline, Embase, and PsycINFO syntax developed by Canada's Drug Agency.

Published Search Filters

View a PubMed search for articles about search filters.

The search strategy used in the link above is: search filter*[tiab]

Aging, Bereavement, & Palliative Care

Australia's CareSearch Palliative Care Knowledge Network has developed several filters to focus search results on subjects relevant to palliative care. All filters in PubMed syntax.

Conditions & Clinical Speciality

Several trusted groups have developed filters to focus search results on particular conditions.

Glaucoma
The Flinders Centre for Ophthalmology, Eye and Vision Research and Flinders Filters developed this filter to provide easy access to the glaucoma literature. All filters in PubMed syntax.
Heart Failure
Developed and validated by CareSearch Palliative Care Knowledge Network and Cancer Council Australia, these filters focus on English language articles about heart failure and on issues specific to heart failure such as anemia, devices, and depression. All filters in PubMed syntax.
Lung Cancer
Developed and validated by CareSearch Palliative Care Knowledge Network and Cancer Council Australia, these three filters provide clinicians with an easy-to-use, standardised shortcut to high level evidence in the treatment of lung cancer. All filters in PubMed syntax.
Nephrology
Developed by McMaster Health Knowledge Refinery (McMaster HKR), filters focus on nephrology in general, kidney transplantation, glomerular disease, dialysis, AKI and CKD. All filters in PubMed syntax.
Contraception
Produced by Flinders Digital Health Research Centre in partnership with Sexual Health & Family Planning Australia, these filters focus results on LARCs (Long acting reversible contraceptive methods), Emergency Contraception, and Contraception in general.

General Medical Subjects - Sources for Sharing Searches & Terminology

PubMed Searches Blog

Primary Health Care

PHC Search Filters (Primary Health Care Research and Information Service (PHCRIS), Flinders University)
Follow the One-Click search links to PubMed references relevant to a specific topic.
Facilitating Access to Evidence: Primary Health Care Search Filter
Describes the process of creating and evaluating a search filter for Primary Health Care. The full-text article includes the filter.