We develop a unifying framework to integrate two of organizational sociology's theory fragments on categorization: typecasting and form emergence. Typecasting is a producer-level theory that considers the consequences producers face for specializing versus spanning across category boundaries. Form emergence considers the evolution of categories and how the attributes of producers entering a category shapes its likelihood of gaining legitimacy among relevant audiences. Both theory fragments emerge from the processes audiences use to assign category memberships to producers. In this paper, we develop this common foundation and clearly outline the arguments that lead to central implications of each theory. We formalize these arguments using modal expressions to represent key categorization processes and the theory-building framework developed by Hannan, Polos, and Carroll (2007).
