Suppose you are in line to order a cup of coffee at Starbucks. Suppose someone ahead of you placed an order for 10 cups of Cafe’ Mocha. Suppose there is only one barista, and can only do one cup of Cafe’ Mocha per minute. What do you think will happen overtime? Two things will happen.
- A long wait time will happen for the in-line customers. 10 cups divided by 1 cup per minute = 10 minutes wait time for the next immediate customer! This is Little’s Law.
- A long queue could also ensue if one customer per minute enters the Starbucks store.
What is the remediation to reduce queue length?
Starbucks to put a policy in place… a flow accelerator policy: put a limit on orders… say 3 cups per customer. Limit the WIP, work in small batches!
The same is true for “The Factory”. Limit WIP! Reduce Batch Size! Work in small batches!