The team could quote the number but not explain it
A knowledge services team maintained a chemicals cost curve: a ranking of plants by what it costs each of them to make the product. Its analysts used it every week. The curve came from a subscription, and the method behind it stayed with the vendor who sold it.
That is workable until a client asks why one plant sits where it does. Answering that needs the reasoning, not just the number, and the reasoning was not theirs to give. The team wanted a curve it could stand behind. What it costs to run a particular plant is known best by the people who ran it, so that is where the answer had to come from.
We rebuilt the curve one plant at a time
We brought together former plant and commercial operators covering the plants on the curve, people who had run these sites or sold their output and knew what it actually costs to keep one going. Each plant was its own conversation. What we heard was recorded against the plant it belonged to, so every position on the curve could be traced back to who said what and why.
The work ran over months rather than in a single stretch, because there is no way to cover a whole curve in one sitting. We also wrote the method down as we built it, step by step, so the team could keep extending the curve to new plants once we had finished.
The team owns the curve and can explain it
The function now works from a curve it built itself rather than one it bought. The difference showed up in client conversations. An analyst asked why a plant sat where it did could explain the reasoning and say where the input came from, instead of pointing at a subscription.
Because the method had been written down while it was being built, the team could keep extending the curve on its own, and used the same approach again for the next commodity it needed to cover.
