A system includes a sensor configured to sense first and second physiological signals produced by a source； and a processing device communicatively coupled to the sensor. The processing device is configured to: receive the first and second physiological signals； determine a first value of a signal characteristic； determine a second value of the signal characteristic； access a scaling map having scaling vectors, and each scaling vector having at least one signal characteristic correction value； determine a scaled first value and a scaled second value based on a first scaling vector and a second scaling vector, respectively； and predict a physiological event based on the scaled first value of the signal characteristic and the scaled second value of the signal characteristic.
