1. A subject pulse oximetry monitoring system for processing physiological information of a subject, comprising: a pulse oximetry sensor configured to generate a physiological signal, wherein the pulse oximetry sensor is configured to detect light attenuated by the subject; and a pulse oximeter coupled to the pulse oximetry sensor, wherein the pulse oximeter is configured to: determine a skew metric value based on the physiological signal; determine a correlation lag value corresponding to a peak in a correlation sequence derived from the physiological signal; determine an expected correlation lag value based on the skew metric value; and qualify or disqualify the correlation lag value based on a comparison between the correlation lag value and the expected correlation lag value; determine a physiological rate of the subject based on the correlation lag value when the correlation lag value is qualified; and display the physiological rate of the subject on a display.