An anomaly detector compares a first event from a business activity monitoring system to a second number from an independent trusted source, wherein the first event includes a first number. The anomaly detector determines that the first number from the business activity monitoring system is inconsistent with the second number. The anomaly detector generates a calibration relationship between first number and second number based on time, responsive to a determination that the first number is inconsistent with the second number. The anomaly detector stores the calibration relationship. The anomaly detector receives a third number from the business activity monitoring system at an interval after comparing the first number. The anomaly detector displays the third number to a dashboard. The anomaly detector displays a qualifier to the third number.