1. A method comprising: determining a first distribution of values for a first physiological parameter; determining one or more values corresponding to at least a first tail area of the first distribution, the first tail area extending from at least one measurement of the first physiological parameter toward an end point of the distribution; receiving a specified false alarm rate; establishing a threshold based on the specified false alarm rate; comparing the one or more values to the threshold; and determining that the measurement is representative of a detected event using the comparison.