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Expert Searching

1. When to Use the Cochrane Library

The Cochrane Library is a collection of databases in medicine and other healthcare specialties provided by the Cochrane Collaboration and other organizations. At its core is the collection of Cochrane Reviews, a database of systematic reviews and meta-analyses which summarizes and interprets the results of medical research, which are often considered high-quality in terms of quality and reporting. The Cochrane Library also contains CENTRAL, the Cochrane Central Register of Controlled Trials.

2. Cochrane Library Cool Tools

In addition to their databases, the Cochrane Library offers:

  • Clinical Answers, meant to provide easily digestible, clinically-focused entry points to rigorous research from Cochrane Reviews, to assist in point-of-care evidence-based decision making. Note the topic and recency filters on the left side of the page.
  • Special Collections, highlighting Cochrane Reviews and blog posts on trending topics.

The Cochrane Colloquium offers some free trainings on evidence-based methodologies, as well as free access to two publications outlining systematic review methodological expectations.

  • Higgins JPT, Thomas J, Chandler J, Cumpston M, Li T, Page MJ, Welch VA (editors). Cochrane Handbook for Systematic Reviews of Interventions version 6.0 (updated July 2019). Cochrane, 2019. Available online at www.training.cochrane.org/handbook.
  • Higgins JPT, Lasserson T, Chandler J, Tovey D, Thomas J, Flemyng E, Churchill R. Methodological Expectations of Cochrane Intervention Reviews. Cochrane: London, Version October 2019. Available online at https://community.cochrane.org/mecir-manual.

3. How to Use Medical Subject Headings in the Cochrane Library

Controlled Vocabulary: MeSH

  • The Cochrane Library relies on Medical Subject Headings (MeSH) from the National Library of Medicine, composed of a controlled vocabulary of biomedical terms used to describe the subjects of a journal article. To access the hierarchical listing of terms, click on the “Medical Terms (MeSH)” tab or use the MeSH icon in the Search Manager.
  • After typing in a term in the MeSH search box, matches to the MeSH thesaurus will be displayed along with structured trees that show the hierarchical relationships among related terms.  A summary of search results from different Cochrane databases will also be displayed.
  • Once you have selected you MeSH tree options, you can run it as a search by clicking the “Add to Search Manager” link. It will then be present  in the “Search Manager” tab (second from the left).  

Hierarchy and Subheadings

  • MeSH trees displayed in Cochrane allow you to visualize where your MeSH term sits in the hierarchy of terms and shows any branches off of your term. Selecting “Explode all trees,” allows you to search for your term and any terms that branch from it. Selecting “Single MeSH term (unexploded),” allows you to just search for your MeSH term without branches. If your MeSH term is part of multiple trees, you can select the specific trees you want to search by selecting “Explode selected trees.”
  • A second search box gives you the option to "Select subheadings / qualifiers." Any MeSH can be made more specific by the addition of subheadings. These appear as a drop down menu similar to what’s described above for the “Enter MeSH term” box.

4. How to Use Keywords

Using Keywords

  • Keywords can be any words used to describe your idea or concept.
  • Keywords can be single words or phrases.
  • Use quotes around all phrases to ensure that the phrase is searched together.
  • For more ideas, visit the MeSH database through PubMed and look at the entry terms listed in the MeSH record.
  • Also consider using synonyms, acroynyms, initialisms, variations in spelling, and other closely-related terms used interchangeably to describe the topic.

Keyword Generation

Keywords can be generated by:

  • browsing entry terms in PubMed's MeSH, and synonyms in Embase's Emtree to add additional keywords to a concept;
  • looking at a few key articles and seeing how the terminology is used; and by
  • doing a few preliminary searches and browsing the results to see how the terminology is used.

5. Cochrane Library Pro Tips

Search Field Tags

From the Search Manager tab, you can use field tags to specify where the database looks for the search term. In Cochrane, first type the search term and then the field tag preceded by a colon. e.g. "Cardiology":ti looks for cardiology in the title

  • :ti - Searches the Title field

  • :ab - Searches the Abstract field

  • :kw - Searches the Keyword field

  • :au - Searches the Author field

  • :so - Searches the Source field

  • :pt - Searches the Publication Type field

  • :tb - Searches the Tables field

Proximity Searching in Cochrane

  • Cochrane allows for proximity searching through the use of two operators (NEAR or NEXT), along with a number to indicate the proximity of the words .
  • Proximity search using NEAR: Use NEAR/ with a number to indicate proximity of terms either before or after each other. For example, “antidepressant NEAR/10 narcolepsy” looks for the word antidepressant within 10 words of narcolepsy. The default proximity value for the operator when no number is entered is 6.
  • Proximity search using NEXT: Use NEXT to match terms that appear next to each other. E.g. cholera NEXT treat* would return “cholera treatment”
  • Note that the apostrophe within a term is treated as a space. To search for adjacent words in a term such as Down's Syndrome, the best approach is to use NEAR instead of NEXT. The search parameter to use in this case would be: down* NEAR/2 syndrome
  • Hyphenated terms: Hyphens are treated as a space with an associated NEXT operator. The term heart-related will match the same results as heart NEXT related. E.g. evidence-based NEXT medicine

Filters

The Cochrane Library will display your search in tabs by systematic reviews and clinical trials. You can also click on the filter icon next to your search to limit by year.

Truncation

In the Cochrane Library you can use a * at the root of a word to find multiple endings. For example:


arthroplast* will return arthroplasty, arthroplasties, arthroplastic, arthroplastics, etc.

mobili* will return mobility, mobilization, mobilisation, mobilize, etc.

You can also use a ? as a wildcard to search for letter variants within a word (e.g. wom?n finds women and woman)

Wildcards, Truncation, Proximity Tricks

Type of Search

Terms with multiple spellings

How To Search

Use the wildcard character with the NEXT operator to match all variations of a term. Note: Use NEAR between a word ending in "'s" and another following word.

Example
st* NEXT john* NEAR wort
Type of Search

Diphthong characters

How To Search

Terms with spelling variations that include diphthongs should be searched with a wildcard character to ensure that all forms of a term are matched. Some more common terms with diphthongs such as "haemorrhage" are automatically matched to their variant spellings through stemming.

Example
isch*mic stroke
Type of Search

Accented characters

How To Search

For all fields except Author, accented characters are not matched by their equivalent unaccented form. To match accented characters use the following options: 1) Use the wildcard characters (* or ?) for a broad match, 2) if the term is displayed on a page you are viewing, copy and paste it to the search box, 3) select the term from a list of accented characters. If entering an accented term in the search box, also include the unaccented version with an OR operator to match all cases.

Partial List of Accent Characters
¤ Ì ‰ „ € ‡ ˆ ‹ Š Ê Œ ý Ž ÿ û ò º ü ù ¢ ÷ Ë Ÿ ¹
Type of Search

Wildcard truncation

How To Search

Use an asterisk (*) to search for multiple characters before, within, or after a search string. A question mark can be used to search for a single character.

Example
abdom* *eclampsia

6. Combining Search Terms and Concepts

Boolean Operators

  • A comprehensive and systematic search of the Cochrane Library includes both controlled vocabulary (MeSH) and keyword terms.
  • Boolean operators are used to combine search terms. In the Cochrane Library, you can use the operators AND, OR, and NOT.
  • Boolean operators MUST be used as upper case (AND, OR, NOT).
    • OR—use OR between similar keywords, like synonyms, acronyms, and variations in spelling within the same idea or concept
    • AND—use AND to link ideas and concepts where you want to see both ideas or concepts in your search results
    • NOT—used to exclude specific keywords from the search, however, you will want to use NOT with caution because you may end up missing something important.
  • Go to the “Search Manager” page to combine searches. This is where your search history is located during your search session.
  • To save searches and access your search history, sign up for a Cochrane Library account.

7. Saving Your Searches

To save searches and create alerts in the Cochrane Library, you must first create an account.

  1. Sign up for a Cochrane Library account.
  2. Once logged in, go to the “Search Manager” tab (the tab directly to the right of the default “Search” tab). Towards the bottom of this page there is a purple drop-down menu labelled “Save this search” with an option to “Save as”
  3. To create an alert for a saved search strategy, click on the “View saved searches” link. In the window that opens, select the checkbox for “e-mail alert” for the individual search

8. Printable PDF Handout