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Metric Design & Product Sense1 / 3

2 min lesson

Decompose into a driver tree

Explain your answer to "Why is a driver tree more useful than a standalone north-star number?" Add one concrete detail from the lesson.

Step 1 of 3

Decompose into a driver treethe north-star as a product of queryable inputs

A north-star you can only observe is hard to act on. A north-star you can decompose tells engineers exactly where to look when it moves. Break it into the harness stages that multiply into it.

THE RUN-SUCCESS DRIVER TREE

Interactive diagram. Step through it with the Next and Previous controls below, or Tab to a region to read its detail.

diagram: flow

The north-star is the product of these stage SLIs - not their average.

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Full explanation

Full explanation

Say it like this

“I'd give the family first: the north-star is the share of agent runs that reach an accepted edit within the latency budget over a rolling 7 days; the two guardrails are cost per run and p99 latency; the counter-metric is the false-accept rate of bad edits.”

Watch out

A north-star with no counter-metric invites gaming. If "success rate" can be raised by making the agent answer less ambitiously, you have built an incentive to ship a worse product. Always pair the optimization target with the thing it would quietly sacrifice.

QAn interviewer asks you to propose a single reliability metric for the agent. What distinguishes a strong answer from a weak one?