MONO91 Automatic Indexing chapter Mary Elizabeth Stevens National Bureau of Standards 1.3 Derivative vs. Assignment Indexing At least part of the provocation and controversy with respect to the possibilities for the use of machines in indexing is due to confusion as to what type of indexing is meant. This in turn relates to a much older and broader controversy--that between "word" or "catchword" indexing on the one hand and "subject indexing", "concept indexing", or "controlled indexing" on the other. In terms of operational definition, the contrast is best expressed in Luhn's dis- tinction between index entries that are derived from the text of an item itself and those that are assigned to it from a list or schedule of subject categories, descriptors and the like, which exists independently of the text of the item (Luhn, 1962 [372]). [OCRerr]lI In general, the differentiations that are made for the broader controversy, and the claims and counter-claims made by the enthusiasts of either school, provide background for the distinctions that should be made between various automatic derivative indexing operations and whatever possibilities may be demonstrated for assignment indexing by machine. In his text on information storage and retrieval Kent (1962 [315) ) contrasts word index- ing as used in permuted keyword indexes, concordances and "pure" uniterm systems with controlled indexing which "implies a careful selection of terminology used in indexes in order to avoid, as far as possible, the scattering of related subjects under different headings." He notes elsewhere that word indexing requires little subject-matter training on the part of the indexer and little skill in indexing as such, and adds: "It is this type of indexing that a machine can perform well"21 Like Kent, Bernier thinks that true subject or assignment indexing requires highly trained human indexers. He says further: "The difference between subject and word indexing has been unclear at times. Both types employ words, but only true subject indexing employs them with discrimination. Word indexing leads to omission of entries, scattering of re- lated information, and a flood of unnecessary entries. Word indexing uses words as they are found in the material indexed with a minimum regard for standardized meaning..." 3/ Herner provides a further amplification of differences that are pertinent to con- sideration of indexing by machine, as follows: 1/ 2/ 3' 4' See also Herner, 1962 [266], p.5; Skaggs and Spangler, 1963, [557], p. 60; Slamecka, 1963 [558], p.224. Mooers makes a similar distinction between "index terms which are words or phrases extracted from the text and stylized conceptual terms--cliches --which are assigned to the text", 1963 [423], p.4. Kent, 1962[314], p.268. Bernier, 1956[54], p.23. Herner, 1963 [267], p. 183. 13