A useful KPI workshop ends with fewer charts, not more. We ask each stakeholder what decision they made last month using analytics. If the answer is "none", that metric leaves the board.
We then map one north-star outcome to a small set of input metrics the team can influence within a sprint. Vanity volume metrics stay in a separate archive report.
The final artefact is a one-page metric sheet: definition, source event, owner, and review cadence. That sheet becomes the contract between product and engineering for instrumentation work.
Follow-up matters. Two weeks after the workshop we check whether the first report used the new definitions. If not, the workshop failed — not the team.