Four Gauges, One Alarm: Why Adding a Signal to the Drift Report Isn't Free
Four Gauges, One Alarm: Why Adding a Signal to the Drift Report Isn't Free Post #28 closed the IPRB's tolling discretion gap by giving the Threshold Calibration Board a new job: track the rate of Tolling Exception grants as a fourth signal inside the Empirical Drift Report, alongside the three it already watches — false-clearance drift, false-capture drift, and (from last week) tolling-grant drift. That felt like a clean addition at the time: reuse the existing report, reuse the existing Emergency Recalibration Trigger, done. But the EDR's entire job is deciding when drift is *real enough* to fire an emergency recalibration, and that decision was calibrated — the 25% false-capture bar in post #26, the 24-month review cycle in post #25 — against a report tracking two signals, then three. Bolting a fourth signal onto an alarm system built and tuned around fewer signals is not a free addition. It changes the odds the alarm goes off by chance alone, and CBR has never actually a...