A method for estimating the sales of specialty products includes defining a first product specific universe using wholesale purchasing data to determine a product specific store size for a first group of retail outlets. A second product specific universe is defined using sampled retail sales data to determine a product specific store size for a second group of retail outlets, which were not represented in the first group of outlets. Geo-spatial projection is applied to the first and second product specific universes to determine product specific projection factors for retail outlets in the first and second universe. The product specific projection factors are then applied to sampled retail sales data for the product to estimate the sales of said specialty product in unsampled outlets. Preferably, the retail sales data includes prescriber information and the resulting estimates are attributable to individual prescribers authorizing the specialty product sale.