Author co-citation analysis analyzes the author cocitation frequency matrix to infer the intellectual structure of an academic discipline. However, the term author co-citation has not been fully defined. Because of imprecise definitions and restrictions of ISI databases, many ACA studies may have used various cocitation counts. This imprecise definition of author co-citation can lead to imprecise co-citation counts on the diagonal values as well as non-diagonal values.
Rousseau and Zuccala (2004) present a classification of author co-citation forms.
Pure First-Author Cocitations
The pure first-author cocitation occurs when the reference list of a publication includes at minimum one publication with A as the first or single author and at minimum one publication with B as the first or single author, with one exception that all articles with these two authors (A and B) as co-authors are excluded in the process of computing co-citation frequency. The examples used here come from the reference list of (Sean B. Eom & Farris, 1996). Example A shows that there is one occurrence of cocitation between Eom and Farhoomand. Example B does NOT yield pure first- author cocitation between Smith and Thomas.
Eom, S. B. (1996). A Survey of Operational Expert Systems in Business (1980-1993). Interfaces, 26(5), 50-70.
Eom, S. B., Lee, S. M., & Kim, J. K. (1993). The Intellectual Structure of Decision Support Systems (1971-1989). Decision Support Systems, 10(1), 19-35.
Farhoomand, A. F. (1987). Scientific Progress of Management Information Systems. Data Base, 18(4), 48-56.
Example B taken from Rousseau and Zuccala
Smith, K. & Thomas, T. (1992) The k-procedure, The Gamma Journal.
Thomas, T. & Smith, K. (1992) More details about The k-procedure, The Gamma Journal.