Chipotle has the fastest service of any fast food vendor I go to. Rush hour, takes five minutes max. Go in when they’re nearly empty and I can be out in under a minute. Feels faster than the best McDonald’s times, even if it’s not really. Why is this?
Chipotle does Kanban!
Why do I say this?
Their customer-facing staff are all generalists. They know how to work the register, make all the types of food, and warn the guys behind them when more supplies are needed.
They have a WIP limit of one order per person working the line. The cash register has its own WIP limit of one, or possibly two during the lunch rush.
Customers are the users, the food is the feature. The employees don’t write requirements, they ask you just enough about what you want to satisfy the current stage of development.
The first employee pulls an order from the input queue, which is the line of waiting customers.
That employees take the order through the stages until there’s another, non-busy employee next to them, then hand it off. There is no knowledge transfer, because there are no requirements beyond what’s already piled on your burrito.
The first employee returns to pull the next customer, while the second employee works with the customer for beans, salsa, cheese, and so on, possibly allowing the next employee down the line to pull the customer’s order forward.
At full employee capacity, there is one employee filling each stage and the customers move at a steady shuffle down the line. If there is no need for full capacity, then employees can clean tables, the kitchen etc while a smaller number of employees runs the food line.
At lower employee utilization, better (i.e. faster) employees are able to cover more stages, and are not limited in their performance by the process.
They do Kaizen events whenever something is screwed up. The employee will stop the line, solicit assistance from the adjacent employees or the kitchen as needed, and fix the problem. Work doesn’t flow around in most cases because things are fixed very quickly and quietly.
Let’s look at the key indicators:
They have work tokens (Customers) that utilize single piece flow (the order) and managed through WIP limits (Set dynamically by the resource count).
Resources pull work from station to station, avoiding all queuing for work in progress. (Technically, one order does queue before the cash registers most times)
They stop the line and resolve problems rather than allowing inventory to accumulate.
They have subordinated all other functions to the goal of minimizing customer lead time.