Operational research OR is regarded by many as being in crisis. If OR is taken to be 'classical OR', this is indisputable … If, however, the definition of OR is widened to embrace other systems-based methodologies for problem solving, then a diversity of approaches may herald not crisis, but increased competence and effectiveness in a variety of different problem contexts.

As cited in Jackson (2007, p. 15) - Towards a System of Systems Methodologies (1984)