In this chapter, we covered the idea of continuous improvement by verifying hypotheses. You know hypotheses that are right and that are wrong by using measurement. We call this infinite loop PDCA because of its parts: Plan, Do, Check, and Act. We have completed our value stream map and calculated the process efficiency. You have also got tips about how to remove unnecessary queues and prioritize with algorithms.

In the next chapter, we will see how to plan future deliveries when your work is hard to predict.