MeSH Indexing and Subheading Revision

Preliminary ThoughtsWhy Index Rather than Use Search Engine?

Facilitate Consistent Retrieval Improve Precision

Why Should Others Index?Material Not in MEDLINETopics Not Covered Well?

Preliminary Thoughts (Part 2)Why Use MeSH?

Cost of Maintenance and UpdateCombining Searches

Why Stay Current?Science Marches On

Indexing PhilosophyWhat is Paper About?

Not what is relevantNot what is mentionedNot what it may be important to

Practice Makes BetterCover All Aspects of An Article

General Indexing Practices8 - 15 Headings AssignedMost Specific Possible

Rule of ThreeMajor Topic versus Subjects Discussed

Example of Indexing

Finding a DescriptorUse MeSH Browser

TermString Search

Print EditionsEntry Terms

Understanding The Record

Check Tags Looked For RoutinelyImportant for Narrowing SearchesAges for Human OnlyPregnancy, Always Use Female as WellAnimals

List of Check TagsHumanMaleFemaleAgedMiddle-AgedAdultAged, 80 AND OverAdolescentChildChild, Pre-SchoolInfantInfant, Newborn

Animals MiceRatsRabbitsCatsCattleDogsIn VitroComparative StudyEnglish AbstractResearch Support

TreesMeaning of HierarchyAdvantage of PolyhierarchyAutomatic Explosions

QualifiersSometimes Called SubheadingsSpecifying Aspects of SubjectUsed by Searchers in Narrowing SearchAllowable Values Specific to DescriptorGroups Easily Confused

Adverse Effects-Poisoning-ToxicityChemistry-Analysis

Understanding the RecordQualifiers

Entry CombinationsPre-Coordinated TermMost Indexing Post-Coordination“Representational Integrity”Descriptor Qualifier Combination Prohibited

Replaced by Pre-Coordinated TermQualifier not Allowable

ExamplesEnzyme/deficiency And Disease caused by DeficiencyOrgan/transplantaion and Organ Transplantation

CoordinationFundamental Aspect of MEDLINE indexingMultiple Headings, multiple qualifiersAllows Complexity of ExpressionAllows Refinement of Searches

Use of Coordination First- Descriptors for TopicsSecond-Qualifiers for DescriptorsThird - Coordination of Qualifiers

Current Difficulties

Retrieval AspectsRepresentational Integrity“Special” Meanings

Brief Reminders

RecallPercent of Relevant Found By Search

PrecisionPercent of Those Found Which Are Relevant

Retrieval Effects

Variety of StudiesIndexing ConsistencyEmpirical Studies

Recall for Subheading Alone 40-50%Recall For MH/sh Combinations Even LowerMissing Significant Numbers of Relevant Citations

Representational Integrity

One Meaning – One ExpressionWhy We Use Thesauri Overlap in MeaningAdversely Affect Retrieval

Example: Diet Therapy and Hyperlipidemia

Role of Diet in Treatment of High Cholesterol and TriglyceridesWhat Search Strategy?

hyperlipidemia/diet therapy [mj] AND human [mh]hyperlipidemia [mj] AND human [mh] AND diet [mh]hyperlipidemia [mj] AND human [mh] AND diet therapy [mh]

Overlapping Meanings

Chemistry and Analysis“do not confuse” with analysis, isolation and purification, metabolism, pharmacokinetics

Poisoning and ToxicityPrevention and ControlSupply and Manpower

“Special” Meanings

Meanings Not In Common UseOften Much NarrowerNot Readily UnderstoodRequires Special Training

Examples

AbnormalitiesComplications

Only For DiseasesAdverse Effects for Procedures

Implications for Searchers

Representational Integrity/Overlapping Meanings

Indexing and Retrieval Scattered“Special” Meanings

Retrievals May Be Swamped by Subgroup (Those With the “Special” Meaning)

Hoped-For Outcomes

Improve RecallAccept Some Loss in Precision

More Consistency

Criteria For Improvements

UnderstandabilityReproducibilityUsefulAs a WholeAs an Individual

Comments and Suggestions

Better Names E.g., statistics and numerical data includes some non-numerical material. Data?Abnormalities. Birth Defects?

Altering Rules

Implementation (MeSH)

Review Entry CombinationsChange Heading and SCR RecordsConsolidate Indexing Rules

Review Annotations�

Implementation (Other)

DCMS ChangesTraining MaterialsIndexing ManualCitation MaintenanceCataloging Maintenance