Medical Subject Headings (MeSH®) in MEDLINE®/PubMed®: A Tutorial
Depth of Indexing and the Rule of Three
- For most research articles, every concept substantively discussed should be covered by at least one MeSH heading
- Even negative findings are indexed if discussed
- For articles discussing many subjects, general headings (but as specific as possible) may be used to group related concepts rather than indexing them individually
- Some items, such as review articles, letters, and editorials, are indexed “non-depth,” meaning:
- All major topics are indexed
- All minor concepts required for complete coordination of the major topics are indexed.