Hans Peter Luhn and Herbert M. Ohlman: Their roles in the origins of keyword-in-context/permutation automatic indexing

InNovember 1958, at the International Conference on Scientific Information (ICSI) in Washington, DC, Hans Peter Luhn, of the International Business Machines (IBM) Company, and Herbert M. Ohlman, of the System Development Corporation (SDC), simultaneously and independently presented their new systems for automatic indexing. Luhn called his system “Keyword-in-Context (KWIC) indexing” and Ohlman called his “permutation indexing.” Within a few years, despite the similarities and obvious lack of advantages of one system over the other, Luhn’s KWIC became the de facto standard for title derivative automatic indexing, and Ohlman’s permutation indexing system largely disappeared. A 1965 state-of-the art report on automatic indexing (Stevens, 1965), with an extensive discussion of KWIC and related concepts, did not discuss Ohlman’s work, though it is cited in the bibliography. A 1966 retrospective review of the KWIC concept gave a slight mention of Ohlman’s work on permuted indexes, but uses the phrase “. . . when Luhn invented the KWIC index. . . .” (Fischer, 1966, p. 58). By 1995, Wellisch’s (1996) handbook on indexing had no mention of Ohlman and stated “Luhn, who first published the successful application of his idea in 1958, called his method KWIC . . . and it became, indeed, the first and to this day the only fully automatic indexing method” (pp. 258–259).