“We are often asked how to sustain lean changes. A kaizen event produces many positive changes, a lean project reduces inventory, and we want to gather up the gains and hold them tight so we do not lose them. Without effective leadership at the site where we have made those changes, we will with certainty lose those gains. Very few self-maintaining systems exist. In fact, the second law of thermodynamics covers entropy, which means chemical systems will tend over time toward the state of least energy–things tend to decay over time. The concept of entropy also applies to culture. Culture tends to decay over time unless there is continual new energy being fed into the system to keep it going. In the case of societal systems, leaders provide that continuing source of energy, which allows them to maintain, develop, and grow the culture in which they live and work. Pull out the leaders at any point and the system will resume decaying.”

Toyota Culture  by Jeffrey Liker & Michael Hoseus (McGraw Hill, 2008) p. 318.