Situation
Order volume had grown by roughly half over two years. Nothing about how the order was promised had changed with it.
Purchasing, the warehouse and customer service each held a defensible view of what was on order and what was available, and none of the three matched. Customer service quoted from the order system. The warehouse picked against what was physically on the floor. Purchasing worked from supplier confirmations that reached the order system only after goods were booked in. On any given morning the three numbers differed by enough to matter, and the difference was resolved the same way every time: someone walked down to the floor, or picked up a phone.
That worked while volume was small enough for everyone to know the exceptions by name. At the new volume it produced late promises, duplicated counting and a steady stream of credits. The commercial cost was visible in the accounts as service failures and expedited freight; the operational cause was not visible anywhere, because the checking that held the process together happened outside every system that recorded it.
We were asked in after a quarter in which on-time dispatch fell below the level the largest two accounts had contracted for. The board wanted to know whether the answer was a new system. It was not, and saying so early was the first useful output of the work.