1. A computer-implemented method of determining expected base sales for a product, comprising: obtaining sales data for a product sold at a point of sale location, the sales data organized in a time series over a time period; identifying a promotional event for at least one of the product and the point of sale location; excluding sales data corresponding to the promotional event from the sales data to form remaining sales data; processing the remaining sales data using a smoothed moving average model involving a plurality of passes through the remaining sales data; generating expected base data for the product based on the smoothed moving average model; and outputting the expected base data representing expected sales for the product to a user.