A Century of Citation Indexing

It has been 60 years since I began my career in information science. Since that time there have been huge changes in technology that are reflected in the way that scientific and scholarly information is disseminated, retrieved, and evaluated. The younger generation of scientists in Turkey and elsewhere will not even remember Current Contents or the huge printed volumes of the Science Citation Index. In its first generation of life, Current Contents became the compulsory reading habit of scientists throughout the world. Then in its second generation of life, we began to publish in Current Contents the series called This week's Citation Classic. Over the next 15 years, we asked thousands of authors to write commentaries on their highly cited papers. Four thousand of these one-page commentaries can be found at (http://www.citationclas-sics.org/). Quite often authors would say that these were not necessarily their most important papers. So when I was asked to write a commentary about my 1955 paper in Science1 I had to point out that this primordial paper on Citation Indexing was neither my most cited work nor my most significant. My 1972 paper in Science, 2 on using citation analysis to evaluate journals, has attracted much more attention. My most-cited work is in fact my 1979 book, Citation Indexing. 3 Books, like review papers, are easy ways to refer to an author’s work in a general way. However, tracing the genealogy of citations to my 1955 paper reveals the evolution of the concept of citation indexing -- from a system for information retrieval to a tool for research evaluation. In a paper that I had prepared at the request of the then editor of Science in 1995, I suggested that the tail was now wagging the dog 4. I will say more about this later. Indeed, this was the theme of my Keynote Address at the last COLLNET conference in Dalian, China. I feel honored to have been invited to COLLNET again.