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14 series in. 4 alerts out.
An outpatient practice billing several payers, 60 days of remits, 14 series. On day 43 one payer started requiring additional documentation for one procedure code. The all-payer denial rate on the dashboard never left its normal range. Find the pair.
Every number on this page is computed in your browser right now, by the same CUSUM and Bayesian changepoint code that runs in production. Nothing here is a screenshot.
The comparison that matters
Against the rule most teams actually ship
The standard configuration is a percentage or sigma threshold against a trailing mean, evaluated per metric. Run it over the exact same 14 series and count what lands in the channel.
The false-alarm count is not a judgement call. The incident was injected at a known index, so every naive alert before that index is wrong by construction.
What the engine found
Detection run
| Metric | Trend | Baseline | Now | Change | Confidence | Method |
|---|---|---|---|---|---|---|
Denial rate payer=Aetna, code=97110 | 7.00% | 24.8% | +254% | 99.9% | CUSUM | |
Days to payment payer=Aetna, code=97110 | 25.082 | 43.730 | +74.3% | 99.9% | CUSUM | |
Appeal overturn rate payer=Aetna, code=97110 | 31.4% | 67.8% | +116% | 99.9% | CUSUM | |
First-pass yield payer=Aetna, code=97110 | 92.2% | 69.2% | −24.9% | 99.9% | CUSUM |
Show your work
Denial rate · payer=Aetna, code=97110
Baseline mean μ = 0.0039 and σ = 0.1089, both computed from the first two thirds of the day-over-day percentage changes. The slack k = 0.0545 is half a sigma, and the decision boundary h = 0.4357 is four. The accumulator runs on percentage changes rather than raw levels so a healthy growing series cannot drift across the boundary on its own.
alert if |Δ| > 20% vs 7-day mean fired 8 times across this one metric, including 1 before anything was actually wrong. The statistical pipeline sent one message, on the day the regime actually changed.
What lands in Slack
One message, with the work already done
- 1.Pull the Aetna remits for 97110 since Aug 11 and read the new CARC/RARC combination.
- 2.Check the appeal clock on the earliest affected claims before the window closes.
- 3.Hold or amend outbound 97110 claims to Aetna until the documentation requirement is confirmed.
The written cause is generated only after the statistics confirm the change. The model never decides whether something is an anomaly — it explains one that has already been established. Getting that order backwards is how these products hallucinate.