Page 139 - DLIS405_INFORMATION_STORAGE_AND_RETRIEVAL

Information Storage and Retrieval

Notes MeSH- application - I

• The 17,000 word MeSH vocabulary is divided into complex hierarchical tree structure.
• There are 16 main top level categories in the hierarchical structure which further give rise to
branch like tree structure sub categories in order of their increasing specificity.
• The MeSH tree structure allows to find relevant MeSH terms and corresponding articles in
PubMed even when only general concept areas are known.
MeSH- application- II
• The MeSH hierarchical tree structure allows to have a control on both precision and recall.
• Recall- The MeSH allows to broaden the domain and increase the recall by fetching the related
articles as well.
• Precision- The MeSH tree structure leads to specificity and hence increases precision.
• For a proficient MEDLINE searcher - Right balance needed between precision and recall.

MeSH- application- III
• Descriptors- Also known as Main Headings, Descriptors are used to index citations in NLM’s
MEDLINE database, for cataloging of publications, and other databases.
• Publication Characteristics- Although MeSH Descriptors, these records are unlike other MeSH
Descriptors in that they indicate what the indexed item is, i.e., its type, rather than what it is
about, for example, Historical Article, Editorial
• Geographics-Descriptors which include continents, regions, countries, states, and other geo-
graphic subdivisions.
• Qualifiers-There are 83 topical Qualifiers (also known as Subheadings) used for indexing and
cataloging in conjunction with Descriptors. Qualifiers afford a convenient means of grouping
together those citations which are concerned with a particular aspect of a subject. For example-
Liver/Drug effects.

MeSH- relevance to Information Architecture - I
• Mesh Tree structures successfully incorporate the following four major IA components:
• Organization System
Whole tree organized into 16 main categories
Further organized into sub-categories
Each heading is labeled in a decreasing order of spectrum (range)
• Labeling System
Labels contain terms which are directly/indirectly related
Poor labels can ruin a good organization or navigation system

MeSH- relevance to Information Architecture - II
• Navigation System
Global (what’s important)
Local (what’s nearby)
Contextual (related)

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