Theories of how public relations is practiced continue to develop. The original four models of public relations were a good starting point for describing the key activities that public relations people did: communication and research. They gave us a way of organizing our concepts by types of public relations practice. James E. Grunig proposed to move on from the models of public relations to more specific sets of measurable variables: symmetry and asymmetry; the extent of one-way versus two-way communication; the use of mediated and interpersonal forms of communication; and the extent to which public relations is practiced ethically.²⁹ These four dimensions give us even deeper and more sophisticated ways of thinking about public relations than did the original models. They help us predict more effectively what will and will not work in our practice of public relations.

²⁹ James E. Grunig, "Two-Way Symmetrical Public Relations: Past, Present, Future," in The Handbook of Public Relations, ed. Robert L. Heath (Thousand Oaks, CA: Sage, 2000), p. 28.