A hefty number of holiday in-store shoppers felt Grinched this year when they couldn’t find the products they were looking for on their retailers’ shelves, a new survey found. They showed their displeasure with their feet, defecting in large numbers to a competitor’s store.

According to the survey of more than 1,000 in-store shoppers by Aldata, a producer of retail and distribution optimization software, 31 percent of them discovered that the product(s) they were looking for during the 2011 holiday season were out of stock. And after encountering empty shelves, nearly half of these shoppers (46 percent) headed for a competitor's store.