AbstractA study of the indexing terms of 10,000 documents was conducted for the main purpose of analyzing the frequency of use of the indexing terms, both singly and in combination with one another. The serial number of each document and the indexing terms for it were typed onto magnetic tape using a Remington Rand Unityper magnetic‐tape typewriter, and this information was analyzed by a Univac I computer; the sequence of computer operations is given in a flow chart. The statistical results, presented graphically, include (1) the number of descriptors used to describe the content of a reference, (2) the distribution of use of the total vocabulary as contained in the dictionary (authority list) for the system, and (3) the frequency of occurrence of singles, pairs, and triples in describing individual documents. The data obtained through this analysis are informative, but not sufficient to fully evaluate an information system. Full evaluation would require analyzing the actual output of the system in terms of the desired output.