I have noticed that Professor **Ackoff** (or even I) can make a good theory work in practice, at least well enough to demonstrate its application. But can we expect management practitioners to follow our guidance, just from our writing management books and giving workshops?

— Peter Jones (2009)

**Ackoff** (1962)... differentiates between iconic models, which use the same materials but involve changes in scale, analogue models which also involve a change in the materials used in building the model, and symbolic models which represent reality by some symbolic system such as a system of mathematical equations.

— Shatrughna P. Sinha (1993)