Tall or flat: The microfoundational bathtub and the water of practices

James Coleman’s ‘bathtub’ (or ‘boat’) model offers a multi-level account of organizations and society in which individuals’ behaviours provide the essential microfoundations of explanation. The bathtub model has become influential in strategy, organization theory, entrepreneurship studies and many other domains. This Essay warns against casual importation of Coleman’s underlying assumptions, especially its tall ontology of micro and macro levels, and proposes three tests for their analytic utility: agentive, normative and material. Microfoundational assumptions particularly jar with the flat ontology of practice theory important in Institutional Theory and Strategy as Practice. The Essay uses water as a unifying metaphor to show how the underweighting of practices in the bathtub model leads to overconfidence in management policy and truncated explanation in management research. The Essay proposes in place of the bathtub a visual model whose flat ontology implies the research importance of practice biographies, longitudinal perspectives, plurality, deep site immersions and socio-materiality.