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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