The ability to evaluate the impact of promotions should provide one of the best benefits of a data warehouse. Earlier, in the section on Trend analysis, we noted that we need to couple the changes in the dimensions with the fact trend analysis. In order to determine the effectiveness of a promotion, we must be able to analyze product sales during several different periods of promotion, as well as during periods of 'non-promotion'. Adding in who buys the product is not as easy as it seems. Manufacturers sell to dealers who, in turn, sell to the stores and then finally they sell to the consumer.
Some promotions are for dealers and some promotions are for the consumer.
Nevertheless, that is what many CPG manufacturers are doing. Food chains are developing programs that will track point of sale activity by customer. This will let them create highly targeted marketing and promotion programs, with price breaks and coupons developed for individual customers. This not only will make more complex data warehouses but they will be much, much larger than is possible today. The return on investment, however, is such that these will happen as soon as the technology is capable.