Managers are not confronted with problems that are independent of each other, but with dynamic situations that consist of complex systems of changing problems that interact with each other. I call such situations messes. Problems are extracted from messes by analysis. Managers do not solve problems, they manage messes.

Russell L. Ackoff (1919–2009) American organizational theorist, consultant, management scientist

“The future of operational research is past,” The Journal of the Operational Research Society, Vol 30, pp.93-104. (1979)