I recently published an essay on the operationalization of professional identity constructs with Dr. John C. Lammers at the Journal of Professions and Organizations. We take an institutional logics approach to specifying the measurement of professional identity. We argue that the measurement of such constructs should include indicators of belonging, attachment, and belief. We offer a multilevel confirmatory factor analysis as exemplary evidence. Theoretically, the piece should be of interest to scholars of professionals and professions. The piece should also remind practitioners that professionals hold a complex web of ideas about their work, and that being a member of a profession, being attached to the profession, and holding beliefs consistent with the prevailing norms of a profession are related but not the same.