Indexing articles for MEDLINE

If you've ever wondered how articles are indexed and who does the indexing for MEDLINE, here's a few details.

• Altogether, about 100 indexers perform the indexing for the National Library of Medicine (NLM) and they are all trained by NLM. Indexers have at least a Bachelor's degree in life sciences, attend a two-week formal training class at NLM, and undergo continuous review for a year. The required production rate is 4 articles per hour.
• Indexers work in an online environment which provides extensive validation and 'reminder' programs to enhance consistency and accuracy.
• The sequence is: understand the subject content of the article, apply MeSH terms to cover all topics substantively discussed, apply 10-12 MeSH terms per article, indicate major points of the article with an asterisk, apply the subheadings, apply check tags (organism, age, gender, etc.)
• Authors frequently want to know how to select keywords for their articles, but NLM doesn't use author-assigned keywords in MEDLINE. Only keywords assigned from the Medical Subject Headings (MeSH) are used. NLM finds that authors frequently choose MeSH terms that are too broad - NLM policy is to select the most specific subject heading possible. A tip for authors from NLM is to use their preferred keywords in the title or abstract where they will be retrievable via textword searching.

For more information:
FAQs about Indexing