Migration patterns of U. S. Ph. D. s among disciplines and specialties

Patterns of migration among disciplines and specialties are examined using data from a large survey of U. S. Ph. D. s in a broad range of fields. Mappings of scholarly fields are derived from the migration patterns and these mappings are largely consistent with results from previous studies using citation flows and other measures of field similarities. Migration patterns suggest that there are two boundaries dividing the fields in this analysis, and that hierarchical relations among disciplines are weak or absent. In contrast, specialties within a discipline are more likely to exhibit structural hierarchies.Revised version of a paper presented at the George Sarton Centennial, University of Ghent, November 1984.