“Lean” is a philosophy that considers wasteful the expenditure of resources for any goal other than the creation of value. In 1990, “Lean production” was a phrase used to describe the Toyota Production System in the influential book The Machine that Changed the World (Womack, Jones, and Roos, 1990). Although Lean originated in manufacturing, it can be applied to any process, whether operational or administrative.

In health care delivery, “value” can be defined as those steps that potentially improve patient health, such as physician-patient face-to-face time, technician time, or image acquisition time. Time and resources spent that interfere with value delivery is considered waste. Patients and payers appreciate and pay for value (things that improve health) and desire nothing else.

Wastes in health care have been categorized into 8 major forms, derived from Lean production philosophy, and can be remembered by the helpful mnemonic, “Wisdom to change.”