Informationsordbogen (2005) defines "uniterms" as a kind of derived indexing terms from the text being indexed. It is a kind of indexing method related to post-coordinative indexing. By uniterms is understood the analysis of compound words into conceptual units. For example "fruitbox" into the uniterms "fruit" and "box".


The Uniterm system is now only of historical interest. One of the interesting historical findings was that the Cranfield I experiments compared Uniterm with subject headings, the UDC and Facetted classification and found that Uniterm was superior. "The results indicated that the Uniterm performed as well as, if not a little better than, more conventional indexing systems, with the added advantage that the Uniterm system required no intellectual effort at the indexing stage" (Ellis, 1996, p.4).


". . . the Uniterm system, devised by Taube [Documentation, Inc., 1953]. This used uncontrolled, single words extracted from the text of a document. Difficulties inevitably arose in a situation where only single-word terms were available to deal with synonyms, homonyms, generic searches, and other problems. Uniterms frequently have different meanings depending on context, application, or viewpoint. Lacking qualifiers, they are unable to express these specific differences. For example, the concept of 'thermal insulation' is very different from that of 'electrical insulation' and the single-word term 'insulation is inadequate to distinguish between them. The system in its pure form did not last long, as the Uniterms were inadequate for specific indexing and difficult and ineffective in searching. It was eventually superseded by vocabularies containing significant numbers of 'bound' or compound terms [indexing phrases]. These early thesauri began to control synonyms and homographs, and to display hierarchical and associative relationships between terms". (Aitchison & Clarke, 2004, p. 7).





Aitchison, J. & Clarke, S. D. (2004). The thesaurus: A historical viewpoint, with a look to the future. Cataloging & Classification Quarterly, 37(3/4), 5-21. Co-published simultaneously as: The thesaurus : review, renaissance, and revision. Ed. by Sandra K. Roe & Alan R. Thomas. New York: Haworth Information Press. (Pp. 5-21).


Andersen, J.; Hjørland, B.; Hoel, I. A. L.; Larsen, P. S.; von Branitz, S. S. & Slente, F. (Eds.). (2005-). Informationsordbogen-ordbog for informationshåndtering, bog og bibliotek. Copenhagen: Udgiverselskabet Informationsordbogen. http://www.informationsordbogen.dk/


Documentation, Inc. (1953). Installation Manual for the Uniterm System of Coordinate Indexing. Documentation Inc., Washington, DC. (LYR22450). 31pp.  

Ellis, D. (1996). Progress and problems in Information retrieval. London: Library Association.


Krug, J. F. (1964). A Comparison of the UNITERM, descriptor and role-indicator methods of  encoding literature for information retrieval. MA-thesis, The University of Chicago. (ORDER NO: AADTM-11218). 

Taube, M. (1955). Application  of  the  Uniterm  System  and  the association of ideas to a special library file. Documentation Inc Bethesda Md. Report No.: TR-10. NTIS Accession Number: AD-093 969/4/XAB. 


See also: Assigned versus derived indexing; Indexing; Indexing phrase (Core concepts in LIS); Post-coordinative indexing; Semantic primitives.





Birger Hjørland

Last edited: 26-07-2006