The design of any particular PBE, like research projects in general, is shaped and conditioned by the nature of the research problem and questions and hypotheses that are to be addressed. It is because of this that ‘design’ is not a foregone conclusion. Taking the ‘problem’, the ‘purposes’ and the ‘research questions’ as the point of departure mitigates against the a priori application of a favoured methodology or design brief that appears to fit the context of the PBE. There will, of course, be situations where PBEs are particularly amenable to treatment through ‘off the shelf’ and established data-gathering models and research designs. It is always tempting to construe or filter a PBE outwards through the respectable maxims of social science disciplines. This has its advantages. It is possible to utilize the conceptual tools developed as part of disciplinary structures to illuminate the ideas base of the PBE. The sociological concepts of ‘norms’ and ‘statuses’ may be activated in the analysis of the organizational structure of hospitals. Similarly, the psychological concepts of ‘attitude’ and ‘personality’ may be activated in the analysis of the decision-making behaviour of police trainers. However, there is also the potential immanent in social and behavioural science disciplines to intellectually constrain an enquiry, to limit its conceptual horizons, and (possibly) create somewhat stereotypical operating conditions for the practice of data gathering. In PBE we try to avoid stereotyping research design. We are particularly concerned that PBEs, following a certain television commercial, are not ’ology led. We are not saying here that a particular methodology is taboo. Rather, we are guarding against the presumption that social and behavioural sciences are the necessary and sufficient starting points for enquiries. Under certain conditions they may well be; under other conditions they will not be appropriate. A thoughtful methodology for a PBE ought to be a servant of that enquiry.