An empirical model of the price relationship between distribution stages is developed based on the Shiller lag. The assumption of constant returns to scale is relaxed to incorporate changes in the volume of shipments. An iterative GLS methodology is developed to estimate the model. Tests for symmetry, length of adjustment, and the amount of price transmission are outlined. An application using the change in the retail price of tomatoes based on shipping point price changes is described. Results suggest that the supermarket chain does not respond differently to price increases versus decreases at the shipping point level.