The available information set is
First, you have the UPC standard data at the weekly level that provides information about sales, and prices and profits. Then you have promotional data that essentially says what products are advertised this week. Finally, you have demographic and competitive characteristics. So we know this store has X percentage of people that have a college education. Or maybe we know that the competitor is located directly next door to the store. In that case you might say, ``well, my stores are right next to my competitor, so people should do a lot of comparison shopping and are going to be really sensitive to price changes.''
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