What are Candidate Terms?

Indexers may find that concepts discussed in articles are not adequately covered by an existing Emtree term. In such cases a candidate term may be indexed, together with a broader Emtree term covering the new concept at a higher level (an “umbrella” term).

For example, when a new antivirus agent is designated as a candidate term, indexers also assign the broader term antivirus agent. For candidate drug terms, the term unclassified drug is also indexed.

Search tip: to find articles in which new antivirus agents have been indexed as candidate terms, search using the terms antivirus agent and unclassified drug.

More than 100,000 candidate terms – drugs, diseases, devices and other terms - are proposed each year, including many which are never indexed more than a handful of times. Frequently indexed candidate terms are evaluated regularly for possible inclusion in Emtree, including synonyms which may have been separately indexed as candidate terms. For new drug terms, a CAS Registry Number is also assigned if possible.

In the case of drugs, new entities may initially be designated as laboratory codes and only later using chemical names, trade names or generic names. In Emtree, the preferred term is always the generic name, if it is available. When older terms are replaced in Emtree by newer terms, articles with the older index terms can be backposted so that the old terms are replaced by the new index terms.