Post-coordinate indexing

Indexing systems in which the combination of terms is not made during the indexing of the document but during the searching in the database. Post-coordinate indexing systems are used in combination with Boolean logic. Search sets are formed and combined with logic "and".


The advantage using post-coordinate indexing is that single words may be combined, which increases recall. The drawback is in particular the increased possibility of false drops.

Example: Literature about "female alcoholics"  is indexed using the terms "human females" and  "alcoholism".

"Coordinate indexing" as a concept and as a method is founded by Mortimer Taube in 1951. He defined is as "a method of analyzing items of information so that retrieval is performed by the logical operations of the product, sum, and complement on the codes in the store".




Bodoff, D. & Kambil, A. (1998). Partial coordination. I. The best of pre-coordination and post-coordination. Journal of the American Society for Information Science, 49(14), 1254-1269.


Bodoff, D. & Kambil, A. (1996). Pre-Coordination + Post-Coordination = Partial Coordination. Working paper. Available at:


Jolley, J. L. (1976). Terminology of coordinate indexing. ASLIB Proceedings, 28(3), 120-128.  


Taube, M. & Wooster, H. (1958). Information Storage and Retrieval. Theory, Systems and Devices. New York: Columbia University Press.

See also Pre-coordinative indexing; Information retrieval manually versus automated; UNITERM




Birger Hjørland

Last edited: 14-07-2006