There is provided a device and method of filtering outliers from physiological values. The method comprises: (a) populating a window with n physiological values taken, in sequence, from a sequence of physiological values, wherein n is a positive integer； (b) determining whether the variability in the physiological values within the window is less than a predetermined threshold； (c) responsive to the variability in the physiological values within the window being less than a predetermined threshold, determining that the window comprises no outliers, and/or responsive to the variability in the physiological values within the window not being less than a predetermined threshold, determining that the window comprises at least one outlier.
