An introduction to biomedical searching for health librarians, MEDLINE, EMBASE & CINAHL

7 February 2017

LIBR534: Databases — Indexes — Interfaces

Icebreaker: what is MEDLINE? Why do we search it? (3 mins.)

“… the medical journal has been used by both clinicians and researchers as the preferred vehicle for keeping up with the latest developments ... medical journals have been systematically indexed for more than 100 years. The role of the journal in the biomedical communication cycle ….has been expanded

profoundly by automated information retrieval.“

Brandon AN, Hill DR. Selected list of books and journals for the small medical library. Bull Med Libr Assoc 1985;73:(2):176–205. [link]

MEDLINE is the index to medical literature

The history of biomedical searching begins in 1879 with Index Medicus & Index Catalogue

(authored by Billings)

Index Medicus – The origin of Medline

John Shaw Billings 1838 – 1913, surgeon, medical librarian & bibliographer

• As the knowledge based in medicine grows, so the medical bibliography grows

• Search complexity has increased exponentially over time

• Google-type searching* has radically changed searching in medicine

• In biomedicine, advances begin in preclinical research first • New drugs & Rx tested using animal models• In-vitro – literally ‘in glass’ • Human studies & epidemiological• Phase I to IV clinical trials

Medical bibliography

Giustini D. How Google is changing medicine: a medical portal is the logical next step. BMJ. 2005 Dec 24;331(7531):1487-8.

Coletti MH, Bleich HL. Medical subject headings used to search the biomedical literature. JAMIA 2001; 8(4): 317–323.

In groups of two or threeTake 10-12 minutes

Appoint a recorder & speakerReview main points in both articles

QUESTIONS TO CONSIDER WHAT IS MeSH? WHAT IS SUBJECT INDEXING

WHAT’S THE PURPOSE OF A CONTROLLED VOCABULARY? IS IT FOOLPROOF?

Share ideas with your peers & instructor

Importance of MeSH

MeSH is:• An acronym for Medical Subject Headings (MeSH)• It is the US National Library of Medicine's controlled vocabulary (thesaurus)• A vocabulary that gives uniformity and consistency to the indexing and

cataloguing of biomedical literature• A distinctive feature of the MEDLINE database; however, there are other

databases in medicine that use controlled vocabularies• MeSH arranged in poly-hierarchical manner called Tree Structures• Updated annually (in 2017, more often…)

Importance of MeSH

• Searchers of MEDLINE/PubMed, library catalogues & other databases to assist with subject searching

• NLM indexers use MeSH to describe content of articles in MEDLINE

• Cataloguers and indexers use MeSH to describe books and audiovisuals at NLM and other medical library collections

Who needs MeSH?

• Premier international bibliographic database in biomedicine • About 24 million citations in MEDLINE plus 2 million ”added” = 26million• 5700+ international journals indexed from 1966-present• OldMedline goes back to ~1940s (back to 19th century)

• Life sciences in scope but concentrated on biomedicine• 850,000+ new entries every year• ~2000-4000 articles added to database every day

• Medline is core of PubMed®; Medline is searchable via OvidSP • Index medicus back to 1879 (see IndexCat - home page) • Created by health librarians at US National Library of Medicine in Bethesda

MD

MEDLINE FACTS:

“…MEDLINE is the product of many information specialists at the NLM: serials librarians who obtain journal subscriptions and check in the individual journal issues; indexers--biomedical

subject specialists--who analyze the subject content of articles and describe concepts that are discussed, using the Medical Subject Headings (MeSH®) controlled vocabulary; and computer

and information specialists who develop and maintain the retrieval system. Every journal issue and article cited in MEDLINE has been reviewed and inspected by many individuals…

US National Library of Medicine. Bibliographic Services Division. http://www.nlm.nih.gov/bsd/indexfaq.html

MEDLINE FACTS:

The 16 top-level categories in the MeSH hierarchy or tree structure are:1. Anatomy [A]2. Organisms [B]3. Diseases [C] many searches involve these two “trees”4. Chemicals and Drugs [D]5. Analytical, Diagnostic and Therapeutic Techniques and Equipment [E]6. Psychiatry and Psychology [F]7. Biological Sciences [G]8. Physical Sciences [H]9. Anthropology, Education, Sociology and Social Phenomena [I]10. Technology and Food and Beverages [J]11. Humanities [K]12. Information Science [L] library and information science index terms here13. Persons [M]14. Health Care [N]15. Publication Characteristics [V]16. Geographic Locations [Z]

MEDLINE DESCRIPTORS HIERARCHY

Most MeSH come with short descriptions or definitions

• See MeSH description for diabetes type 2

• Text written by NLM librarians based on standard reference sources

• Sources are standard texts of subject; similar to sources assignment

• Citations are not given; readers referred to bibliography

Scope Notes

• In MeSH, 82 subheadings are used to describe articles in conjunction with major and minor descriptors

• These subheadings or qualifiers provide a way to group citations together around particular clinical or administrative aspects of subject

• Not every qualifier is suitable for use with every MeSH

• Subheadings also belong to families or groups – and can be exploded

https://www.nlm.nih.gov/bsd/disted/meshtutorial/searchingpubmedusingmeshtags/02.html

Subheadings

By MeSH By Keyword• Indexers do conceptual work

• Subject headings are ‘pre-defined’

• Derived from a controlled vocabulary or theasurus (MEDLINE – MeSH)

• Subject & descriptor fields searched

• More relevant items retrieved

• Indexers index at most specific level

• Subheadings can be used

• Major & minor subject headings

• Searchers do conceptual work

• Keywords not pre-defined

• Search subject, title, author, abstract, content (if available) fields

• Words, parts of words, phrases, names, or combinations

• Irrelevant items “false hits”

• All possible synonyms, alternate terms, variants (e.g. singular, plural, adjectives); variant spellings (Canadian, UK, US)

SEARCHING IN MEDICINE

Medline indexes the full range of biomedical information

Finding best evidence in medicine