An operational research (OR) practitioner designing an intervention needs to engage in a practical process for choosing methods and implementing them. When a team of OR practitioners does this, and/or clients and stakeholders are involved, the social dynamics of designing the approach can be complex. So far, hardly any theory has been provided to support our understanding of these social dynamics. To this end, our paper offers a theory of ‘boundary games’. It is proposed that decision making on the configuration of the OR approach is shaped by communications concerning boundary judgements. These communications involve the OR practitioners in the team (and other participants, when relevant) ‘setting’, ‘following’, ‘enhancing’, ‘wandering outside’, ‘challenging’ and ‘probing’ boundaries concerning the nature of the context and the methods to be used. Empirical vignettes are provided of a project where three OR practitioners with different forms of methodological expertise collaborated on an intervention to support a Regional Council in New Zealand. In deciding how to approach a problem structuring workshop where the Regional Council employees would be participants, the OR team had to negotiate their methodological boundaries in some detail. The paper demonstrates that the theory of boundary games helps to analyse and describe the shifts in thinking that take place in this kind of team decision making. A number of implications for OR practitioners are discussed, including how this theory can contribute to reflective practice and improve awareness of what is happening during communications with OR colleagues, clients and participants. 
Boundary games: How teams of OR practitioners explore the boundaries of intervention