The Most Dangerous Number Nobody Recalculates
The Most Dangerous Number Nobody Recalculates
CPA tripled in six months. Nobody noticed because nobody recalculated it.
The Stale Metric Problem
Every company has a customer acquisition cost they use in planning. It gets calculated once, put in a spreadsheet, and referenced for months. But the inputs change constantly - ad costs rise, conversion rates shift, competition increases. The number in the spreadsheet drifts further from reality with every passing week.
By the time someone recalculates, the damage is done. Six months of decisions were made against a number that was wrong from month two.
Why Nobody Recalculates
Recalculation is tedious. It requires pulling data from multiple sources, normalizing it, accounting for attribution windows, and making judgment calls about what counts. It takes a few hours of focused work. Nobody prioritizes it because the existing number feels right.
It feels right because nobody has checked.
The Agent Solution
This is exactly the kind of task agents excel at:
- Automated data aggregation - pull spend data from ad platforms daily
- Real-time calculation - recompute CPA every week, not every quarter
- Trend alerting - flag when CPA moves more than 15% in any direction
- Attribution tracking - maintain consistent attribution logic across sources
An agent that recalculates CPA weekly would have caught the tripling in month one instead of month six. That five-month difference is the difference between adjusting strategy and running out of runway.
Beyond CPA
Every critical business metric should be recalculated continuously. LTV, churn rate, burn rate, revenue per employee. The most dangerous numbers are the ones everyone trusts but nobody verifies.
Fazm is an open source macOS AI agent. Open source on GitHub.