Within each iteration of an iterative process: (1) a low-pass filter is applied to an actual sales volumes series to extract low frequency components representing a base sales volume series for the iteration; and (2) a locally optimal base sales volume series is determined. A globally optimal base sales volume series is selected from among the locally optimal base sales volume series, comprising an estimated base sales volume for each time period. One or more of the estimated base sales volumes is made available for use in connection with at least one business analysis.