THE DISTRIBUTION OF INDEXING DEPTH IN DOCUMENTATION SYSTEMS

Abstract

Most documentation systems allocate a variable number of descriptors to their documents. From a consideration of indexing as a stochastic process it is suggested that the distribution of indexing depth in such a system might represent samples of a (truncated) mixed Poisson process. Examination of five different systems showed that indexing depth does appear to be distributed in this manner, since a reasonable fit to negative binomial distributions can be made statistically. Factors in the art of indexing which influence the distribution are discussed. As a first approximation the distribution of indexing depth, i, of a system, or of any subset of descriptors in it, is simple Poisson, p(i) = e−m(mi/i!), where m is the average depth of indexing. The results contradict previous reports that a log‐normal distribution of indexing depth is to be expected.

Citation

BIRD, P.R. (1974), "THE DISTRIBUTION OF INDEXING DEPTH IN DOCUMENTATION SYSTEMS", Journal of Documentation, Vol. 30 No. 4, pp. 381-390. https://doi.org/10.1108/eb026586