Every number explains itself

“Where does this number come from?” In every meeting where numbers are shown, this question comes up. And it is usually followed by a second one: “Would controlling calculate it the same way?” If you don’t know the answer you lose the conversation – not because the number is wrong, but because nobody can explain why it is right.

Since this month every number in Pythia explains itself.

Explain mode

An “Explain” switch – or simply the question-mark key – has three levels: off, rules, operation.

• Rules: every number that can be explained gets a dashed frame. Pointing at it opens a card: what the number is, how it was calculated – with the actual values, not a general formula – and which rules apply. A click pins the card.
• Operation: every switch, every filter, every tab explains what it does, which values it knows and what effect it has. A card at the top of every page says what the page actually shows.

The state is in the address. If you want to send a colleague an explained view, you just send the link.

The rule register

Behind the cards sits the rule register: all of Pythia’s agreed calculation and data rules, each with its own ID, title, rationale, formula and parameters. How far back does the anchor reach? When does a previous year count as a build-up year? When does a price change count? For each of these questions there is exactly one rule.

A dedicated page turns the register into a reference work, organised into 14 subject groups – from where the numbers come from, through calculation and display, to access – and searchable by ID, text and formula.

A rule that only exists in the code is a claim. A rule you can look up is an agreement.

Pitfalls

Some numbers are calculated correctly and still misread. A red candle in the calendar year although the year was strong. A slump in the last few days that isn’t one. For such cases there is the “Pitfalls” page: each one with its cause and its remedy. Notes below the timeline link straight to it.

One example: on the order-intake axis, an order day is only invoiced bit by bit – just under half on the same day, almost all of it after three days. If the window reaches into the last few days, Pythia says how complete they are. A drop there is lag, not a slump. We had assumed two weeks of lag; measured, it is a few days.

Next month: returns and credits – the flip side of revenue.