MONO91 Indexes Compiled by Machine chapter Mary Elizabeth Stevens National Bureau of Standards In the Salton project, tests of the value of citation links for the assignment of index terms have been made by comparing the citation pattern of an "unknown" document with those of other documents in the collection to derive a set of five "related" documents, where relatedness is decided on the basis of the magnitude of the similarity coefficients for the citation links. Any index term that appears at least twice in the set of terms previously assigned to the five related documents is then assigned to the new item. In general, approximately 50% of the terms so assigned were also assigned to the same `1new" items by human indexing procedures. 1/ As we have previously noted, however, the advantages of citation indexing are likely to be most effectively applied when used as part of an array of other tools. Tukey suggests, in particular, that permutation indexes of titles, as in KWIC systems, would be of great value as "starter" and "re-check" mechanisms for the use of citation indexes.2[OCRerr] Brownson reports: "Consideration is now being given to the possibility of experimenting with a `hybrid' type of index that would combine permuted titles, authors, and citation data. Such an index might be more useful than any of the individual types of indexes issued singly; and, since no human indexing judgment would be involved, it could be prepared largely by machine and issued rapidly." Williams, while at ITEK, proposed a hybrid integrated index combining listings by authors, corporate authors or author affiliations, keywords-in-context frorn title, and references to works cited by and to works citing an item, and she also developed a sample 4/ format for selected items from several journals in the field of philosophy. - Precisely such a hybrid tool was provided with the Short Papers for the A. D. I. Annual Meeting 1963, and it was indeed issued rapidly. A brief period of only two or three weeks elapsed between receipt of many of the manuscripts and the distribution of two automatically typeset volumes. The second of these volumes contains a KWIC and an author index to these papers themselves, a bibliography and citation index to all papers referenced by them, and KWIC and author indexes to the cited papers, all computer-compiled within this time period. [OCRerr]/ 1/ 2I 3' 4/ 5' Ibid, See also Lesk 1963, E 3s7[OCRerr], p. V-8. Tukey, 1962, L6ll[OCRerr], p. 12. Brownson, 1963 [OCRerr]82], p. 4. T. M. Williams, private communication, dated January 4, 1962. Luhn, 1963 [376], and [377] , pp. 353-38Z. 37