How is "waste" defined in Lean methodology?

In Lean methodology, "waste" is defined as any process activity that does not add value to a product or service. This concept is central to Lean principles, which aim to maximize customer value while minimizing waste. The focus is on identifying and eliminating activities that do not contribute to the final value experienced by the customer.

By classifying activities as value-added or non-value-added, organizations can streamline processes, reduce costs, and improve efficiency. The goal is to create a more efficient flow of work that enhances productivity and quality, removing anything that consumes resources but does not bring significant value.

The other definitions provided do not align with the core principle of waste in Lean. They may touch on aspects of process efficiency or optimization but do not capture the essence of waste as defined in Lean methodology. The emphasis on eliminating non-value-adding activities is what distinguishes the correct definition.