Intellectual exchange is central to progress in any discipline, including political science. The transfer of knowledge, ideas, and techniques takes place in many forums (e.g., advisor-student meetings, conferences, department lounges) and it is no simple task to systematically identify or quantify this interchange. In general though, the fruition of a successful or insightful idea is a published journal article or book. The way in which the author(s) of a published piece of work acknowledges previous or contemporary work that contributed to its development is via references or citations. Thus, while we cannot easily keep track of the entire process of intellectual exchange that leads to publication, citations inform us of other (usually published) work that influenced and contributed to the articles and books that make up the research output of the field. a
a We thank two anonymous referees for helpful comments on content and structure.