Fable
At the post station, only carriages that depart are counted, not those that arrive
The mountain road post station used to have only a dozen letters a day. The stationmaster considered the day safe if he saw whether the carriage left on time and whether the coachman returned.
Later the letters became business contracts, prescriptions, lawsuits, and urgent reports. The carriage still left on time, but recipients often said they had not received it, received it late, or received it with a page missing.
The stationmaster first posted the number of trips on the wall. The numbers looked better and better, and the coachmen were more willing to take short routes, because every trip counted as an achievement.
The shopkeepers began to complain: the post station looked busier, but the number of things actually accomplished had not increased. After one prescription arrived late, the patient's family member held up the good numbers and asked the stationmaster whom these numbers had actually helped.
The stationmaster also wanted to count how many li the horse ran. The groom therefore took detours to make up mileage; the ledger grew thicker, but delivery remained chaotic. The new accountant broke each letter from order intake to signed receipt into several cells: address recognition, sorting, loading, in-transit handoff, receipt confirmation, exception handling.
Only when the recipient confirms and the content is complete does it count as success. At first the numbers were ugly, and many problems that had been hidden by "went out" were exposed. A few months later, the number of outbound trips decreased a little, but far more letters were truly delivered.
The new bookkeeper also classified failures. Some letters had addresses recognized incorrectly, some were lost during handover en route, and some arrived with missing pages. Each type of failure corresponded to a different fix; all bad outcomes could not simply be stuffed into one bucket.
The stationmaster later still looked at the number of trips and the distance traveled, but they served only as auxiliary. What truly hung at the center of the wall was the proportion of complete deliveries and the reasons for failure. The post station finally measured itself by what it was hired to accomplish. Later, when newcomers were onboarding, the old masters no longer started with abstract terms, but had them review that failure: where intuition had been relied on, why the first fix was insufficient, and how the new arrangement kept risk in a place that could be checked. Only when they could explain these details clearly, and also point out when to follow the old way and when to escalate, were they considered to truly understand this approach. Later, they also had newcomers practice this approach: first let the newcomers do it the old way to see how errors emerged; then redo it under the new rules to see which step was blocked in advance and which step left evidence. If newcomers could only recite names, they would still misuse it in similar scenarios; only those who could state the applicable boundaries, costs, and remedies after failure were allowed to take on work independently.