Visualizing the Configuration of Scientific Literature A Study of Disciplinary Relationships
Linda G. Ackerson · Reference & User Services Quarterly · 1999
A Study of Disciplinary Relationships The way in which researchers visualize the structure of scientific literature affects the method by which they conduct literature searches. In this study, citation counts were used to assess the relationships among six scientific disciplines and examine the cross-citation activity of fifty-nine core journals. The results of this study were compared with data from previous studies to create a visual diagram illustrating the configuration of scientific literature. In 1961, Jacob and Monod identified as the missing link in the control of protein synthesis.(1) They described how a minor species of RNA relays the genetic information from the nucleus of a cell to the cytoplasm to synthesize protein. Jacob and Monod were not the first to discover that RNA could serve as a messenger molecule; in fact, that idea had existed since the 1950s. The mystery was how the structural message was transferred. Jacob and Monod's conclusion--that served as a short-lived intermediate that was rapidly formed and destroyed during the process of information transfer--was a vital contribution to the literature. But their introduction of a conceptual model was just as significant, because the model helped other researchers to visualize how functioned within the process of protein synthesis and subsequently influenced the course of research in this area.(2) Mental models also have an impact on how library users approach literature searches. The way in which reference librarians visualize the structure of written scientific literature influences the way in which they pursue, and advise users how to pursue, research inquiries. Having a conceptual model of how information is disseminated and organized, along with a better understanding of disciplinary relationships, enables researchers to plan more effective strategies for gathering information. The following study uses citation counts to develop a mental model for the extent of overlap among the literatures of astronomy, biology, chemistry, geology, physics, and mathematics. Review of the Literature Several previous studies have utilized citation counts to measure the relationships between disciplines. In 1949, Fussler analyzed the serial literature used by physicists and chemists.(3) He used Physical Review and Journal of the American Chemical Society as respective keys to the significant literature of physics and chemistry, chosen because they were the official publications of the major physics and chemistry societies. Fussler analyzed the references from these key journals for the years 1899, 1919, and 1939 and identified the most frequently cited journals in these key journals. From this analysis, six additional chemistry journals and four additional physics journals were added to the two key journals to represent the literature of physics and chemistry. After identifying the major journals to be analyzed, Fussler drew a sample of 3,612 references from the chemistry journals and a sample of 3,920 references from the physics journals. For each title cited in the 7,552 sample references, Fussler assigned a subject label based on the Library of Congress classification given to the journals by the Catalog of Books Represented by Library of Congress Printed Cards or by the University of Chicago depository or its public catalogs. The subject label of chemistry was assigned for titles classified as QD, and physics titles were identified by a QC classification. Fussler then counted the number of references assigned to each subject label to determine which subjects were used in the literatures of chemistry and physics. In 1939, the last full year represented in this study, 12 percent of the journals cited in the key chemistry journals were physics titles, and 10 percent of the journals cited in the key physics journals were chemistry titles. Fussier found low use of mathematics literature by chemists and physicists, and he wondered if perhaps mathematical literature was used by these two groups but not cited. …