Interdisciplinary deliberative research has grown tremendously over the last decade. Theorists are attending more carefully to the findings of empirical research. And empiricists are framing their research in ways that are tailored to track normative-theoretical concerns. The recent surge in empirical work on deliberation, however, has led to a huge proliferation of research designs, general measurement strategies, operational criteria, and even definitions of the phenomenon. The diversity in these approaches has become sufficiently great that it seems worthwhile to step back and take stock lest the expanding deliberative research community dissipate its energies in an ironic lack of effective communication across theoretical and methodological approaches. I survey the main sources of theoretical diversity among normative theories of deliberation, along with the diversity of basic strategies for measuring deliberation that follow from them.