The only way to know how a complex system will behave-after you modify it-is to modify it and see how it behaves.

Management must provide employees with tools that will enable them to do their jobs better, and with encouragement to use these tools. In particular, they must collect data.

One important idea is that science is a means whereby learning is achieved, not by mere theoretical speculation on the one hand, nor by the undirected accumulation of practical facts on the other, but rather by a motivated iteration between theory and practice.

Discovering the unexpected is more important than confirming the known.

Remember that all models are wrong; the practical question is how wrong do they have to be to not be useful.

To find out what happens to a system when you interfere with it you have to interfere with it (not just passively observe it).

The benefits provided by worker participation are twofold. Quality is improved because of the finding and fixing of a very large number of problems, but also, and perhaps equally important, moral is improved.