Main idea

A product team is working on the quality of service reports and relies on a rule held by another team: the list of information required when closing a work order. It has two ways to use it, and each fails in a symmetrical way.

Pointing to the original avoids the copy: you consult the rule where it lives. But if nothing signals that it has changed, you keep relying on what you read six weeks earlier. Copying makes you independent: the copy no longer depends on the other team. But if nothing says where it came from, a year later you have a text that is right or wrong and nobody knows what it rests on.

So each move carries its own debt. A reference requires knowing when its source changes. A copy requires writing down where it came from, when it dates from, and what was reworded along the way. The mistake is neither copying nor referencing: it is doing it without writing down what the move requires.

Why it matters

It gets out of a badly framed debate — should you duplicate or point to the source? — in which each side is right against the other. The criterion becomes checkable: a reference with no change alert is in default, a copy with no provenance is in default, whatever the initial choice.

It also gives a writing instruction for any document that relies on someone else's rule: write down, at the moment of borrowing, what the chosen move commits you to maintain.

Nuances and limits

Being told about changes assumes a mechanism the owning team has to feed; the reference's debt is partly paid by someone other than the one who took it on.

And the provenance of a copy does not stop it from going stale: it only lets you know that it is dated and where to verify it.

Open questions

• What minimal signal can an owning team send when a rule changes, without having to know everyone who relies on it?