DeCS/MeSHDescription, uses, services, updating

Visit of Isabelle Wachsmuth (WHO) and América Valdes (PAHO)

BIREME, São Paulo, 06-17 August 2007

Description• DeCS – the Portuguese acronym for Descritores em

Ciências da Saúde, ie, Health Sciences Descriptors

• Controlled multilingual vocabulary created by BIREME in 1982, fully compatible with MeSH

– Update frequency idem MeSH– Currently available in Portuguese, Spanish and English– Provides for Public Health, Homeopathy, and Science and Health

terminology

• An integrating component of the VHL and GHL, allowing– Meta searching, ie, multiple IS can be searched at the same time– Multilingual searching to literature

Uses• Serves as a controlled (unique, standard)

vocabulary for indexing scientific and technical health-related literature

- at the concept level, it groups synonymous terms into concept units;

• Permits searching by subject (concepts), independently of the language

- natural language used in document titles, abstracts and full texts is ambiguous and therefore leads to long/complex search expressions, lack of specificity and unreliable results

• Hierarchical codes allow for exploding (searching) all terms of a conceptual hierarchy (branch)

DeCS Structure

• MeSH and DeCS Categories

• Types of DeCS/MeSH terms

• Vocabulary Characteristics

MeSH and DeCS Categories

descriptors synonyms

Anatomy [A] 1489 2133

Organisms [B] 3485 7934

Diseases [C] 4228 7728

Chemicals and Drugs [D] 8391 10993

Analytical, Diagnostic and Therapeutic Techniques and Equipment [E] 2234 3575

Psychiatry and Psychology [F] 853 1139

Biological Sciences [G] 2077 2768

Natural Sciences [H] 522 582

Anthropology, Education, Sociology and Social Phenomena [I] 459 691

Technology, Industry, Agriculture [J] 304 669

Humanities [K] 176 137

Information Science [L] 362 449

Named Groups [M] 188 291

Health Care [N] 1121 1695

Publication Characteristics [V] 136 55

Geographicals [Z] 371 290

Subtotal MeSH 24355 37956

Homeopathy [HP] 1950 1469

Science and Health [SH] 218 133

Public Health [SP] 3486 3507

Health Surveillance [VS] 830 1230

Subtotal DeCS-only 4726 3467

Total 29081 41423

Types of DeCS/MeSH terms

• Descriptors

• Synonyms

• Qualifiers

• Check-tags

• Publication Types

Descriptors

• Also known as Main Headings or Preferred Terms

– used for indexing and effective retrieval of document citations.

Types of DeCS/MeSH Concepts

Synonyms

Synonyms, also known as Used For (UF) terms, cross-references or entry terms, have the same meaning or nearly the same meaning as the descriptor and are used as alternate terms in search expressions, obtaining the same search result.

Types of DeCS/MeSH Concepts

Health-related terms that are used for indexing in conjunction with descriptors.

This combination permits retrieving only those citations which are concerned with a particular aspect of a subject.

For example, Steroids/adverse effects, finds documents about the side effects of using steroids

Qualifiers

Types of DeCS/MeSH Concepts

Qualifiers are searched preceeding them by a slash in the Alphabetical index or Keywords in Context index.

Check tags (or Limits)Check tags are generic terms used to limit the scope of research subjects, such as: Male; Female; Humans; Animals; Rats; Cats; Cattle; etc; and age groups

The age groups are :

Infant, Newborn (birth to 1 month) Infant (1 to 23 months) Child, Pre-school (2 to 5 years) Child (6 to 12 years) Adolescent (13 to 18 years)*Adult (19 to 44 years)*Middle Age (45 to 64 years) Aged (65 and older) *according to MeSH/NLM

Types of DeCS/MeSH Concepts

Publication TypesTerms used for describing the document format which allows another means

for restricting the search result.

Examples:

Editorial [Publication Type], Letter [Publication Type], Review [Publication Type], Clinical Trial [Publication Type], Clinical Trial, Phase I [Publication Type], etc.

The list of existing Publication Types is accessible through:

• the DeCS “Tree” index (V – category);• the DeCS “Keyword in Context” index, by writing “publication”; • the “Publication type” index from the information sources.

Types of DeCS/MeSH Concepts

Vocabulary Characteristics

• MULTILINGUAL

• to date, 11 of the MeSH translations have been incorporated to the UMLS (Unified Medical Language System) Metathesaurus

• POLYHIERARCHICAL

• POSTCOORDINATION

• PRECOORDINATION

Multilingual• DeCS is trilingual (English, Spanish and Portuguese)

Arab, Franch, Chinese, Russian and other MeSH translations are candidate languages for the DeCS/MeSH vocabulary in the GHL initiative

• From DeCS the Spanish and Portuguese MeSH terms are exported for the UMLS metathesaurus (Unified Medical Language System)

• To date, there are 11 MeSH translations incorporated into the UMLS Metathesaurus

Vocabulary Characteristics 2 of 5

PolyhierarchicalA descriptor may belong to more than one category or to several branches of the same category.

Polyhierarchy exists due to the multidisciplinary nature of many concepts.

Vocabulary Characteristics 3 of 5

Postcoordination

• Descriptor+Descriptor• Descriptor+Qualifier • Descriptor+Check tag• Descriptor+Publication Type

The act of coordinating two or more concepts at the moment of searching for literature with the objective of narrowing the scope of a subject. The DeCS/MeSH vocabulary permits four types of terminological postcoordination.

Vocabulary Characteristics 4 of 5

PrecoordinationThere are two types of precoordination:

1) Descriptor1/qualifier use Descriptor2

Examples:

HEART/abnormalities use “HEART DEFECTS, CONGENITAL”

PREGNANCY/complications use “PREGNANCY COMPLICATIONS”

2) Descriptor1 AND Descriptor2 use Descriptor3

Examples:

“WOUNDS AND INJURIES” and HEART use “HEART INJURIES”

TRANSPLANTATION and KIDNEY use “KIDNEY TRANSPLANTATION”

Vocabulary Characteristics 5 of 5

DeCS Services• DeCS Server

– for users• Search by Words

– Word – Exact Descriptor

• Search by Index– Alphabetic– Keywords in Context (KWIC)– Tree (hierarchical navigation)

• DeCS XML Server– for computer applications

http://decs2007.bvsalud.orgVHL>HEALTH TERMINOLOGY

The DeCS Search system known as DeCS Server

other language interfaces

DeCS Server

A Sample DeCS Record

Adding new languages

• The Arabic, French, Chinese, Russian and other translations of MeSH are candidate languages for DeCS/MeSH vocabulary in the GHL initiative

– BIREME prepares the installation packages

• The full adoption of DeCS for a given instance of the GHL initiative requires the corresponding translation of the DeCS categories

– BIREME provides guidelines and advice for this activity

– The resulting translation data is formatted according to the current MeSH translation file format (plain text or XML format)

Creation of new categories

• A new category will be added to DeCS under the criteria published in “DeCS Update Guide”

– Lack of a controlled terminology for indexing documents in a health science domain not covered or not fully expressed by DeCS/MeSH;

– Validation of the proposed terminology by the DeCS Technical Committee;

– New concepts may be added to DeCS also under the criteria published in “DeCS Update Guide”.

DeCS homepage. Available at http://decs2007.bvsalud.org/I/homepagei.htm

DeCS description and uses. Available at http://decs2007.bvsalud.org/I/decswebi2007.htm

Guidelines for DeCS Updating. Available at http://bvsmodelo.bvsalud.org/download/decs/DeCS-UpdateGuide.pdf

This presentation: http://decs2007.bvsalud.org/I/DeCS_EVIPNet.ppt

Bibliography

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