Cocited author mapping as a valid representation of intellectual structure

It is generally assumed that cocitation studies of specialties and fields yield valid representations of intellectual structure. To test the validity of this assumption, 5–6 years aggregate cocitation data for 41 authors in macroeconomics and 49 authors in Drosophila genetics (the genetics of fruit flies) were compared with independent judgments of inter-author similarity collected from 14 macroeconomists and 15 geneticists via a card-sorting technique. Non-metric multidimensional scaling (ALSCAL), and Johnson's “smallest diameter” clustering were used to create two-dimensional cluster-enhanced maps. Congruence between maps of cocitations and similarity judgments was assessed using canonical correlation of the spatial coordinates of points (authors) in each of a given pair of maps. Two significant canonical correlations were found in each test. The majority of clusters appeared in both cocitation and judgment maps. In macroeconomics, differences between maps and clusters represent the influence, on judgments, of individual authors' perceived policy orientation. In Drosophila genetics, major differences arise from a time lag in the incorporation of authors' recent work in the formal literature. Cocited author mapping is a valid representation of the intellectual structure in both macroeconomics and Drosophila genetics. © 1986 John Wiley & Sons, Inc.