In het boek On the Mend leggen John Toussaint & Roger A. Gerard uit wat binnen Lean wordt verstaan onder waarde:

Focus on value

(...)

The value test

The goal of every lean practioner is to find what is of value to the customer and deliver it reliably, while removing all extraneous acts and materials from the process. In the strictest definition, everything that is not of value is waste.

But how does one identify what is truly of value for the customer? (...) In manufaturing, lean practioners define value as something for which the customer is willing to pay. Looking at every aspect of production, they ask, would a customer pay for that? The customer would be willing to pay for the widget to be assembled and painted blue, for instance, but would not be willing to pay for a factory to overproduce widgets, truck them to a warehouse and store them until needed. Overproduction and storage are defined as waste.

Bron: On the Mend, Jonn Toussaint & Roger A. Gerard