Which of the following is NOT one of the five core principles of Lean Thinking?

In Lean Thinking, the core principles are designed to create value and eliminate waste in processes. The five core principles include defining value, mapping the value stream, creating flow, establishing pull, and pursuing perfection.

Efficiency, while an important concept in various contexts, is not explicitly listed as one of the five core principles. Instead, Lean Thinking focuses more on delivering value to the customer by optimizing processes and ensuring that every step adds something meaningful without unnecessary waste.

Value is central to determining what the customer desires, flow is about ensuring work progresses smoothly without interruptions, and perfection is about continuously improving processes to enhance quality and efficiency over time. Thus, identifying areas of true value and ensuring a seamless progression towards delivering that value is why the focus is on those principles rather than purely on efficiency as a standalone concept.