Which problem? There are a million things wrong in any particular developed country or village. The question is which things should we focus on? We are starting with the ideas of local knowledge and participation but may still find that several issues are thrown up for focus. Which do we choose? Some ideas from health needs a****sment: we might want to give priority to the area with the larger burden of illness (affects more people, affects people more severely- mortality and morbidity- how many, how bad, for how long). What other ways of prioritizing should we use?
Once we have decided on the problem that will be focused on we can further refine/structure it. The challenges that we are facing in evoke and in the real world are "wicked problems" or "swamps". The areas chosen to be tackled will typically be 'large and complex, involving many interested parties, often with sharply differing beliefs and values.'(Hector et al 2009 doi:10.1016/j.ejor.2007.06.058)