The dependent variable in the Rotterdam model is shown to consist of two additive components: the proportionate change in the average product weight consumed by existing buyers and the proportionate change in the share of total consumers who actually purchase the product. Applying the extended model to household data on salmon consumption in France, results suggest prices have a larger effect on attracting new buyers to the product in question than on getting existing buyers to consume more. However, generic advertising was found to affect consumption intensity but have no effect on market participation in the short run.