The calendars traditionally mark every day in December of Advent, a time of reflection for Christian believers and of preparation for the Nativity and expected return of Jesus Christ. Such calendars are an effective tool to convince early holiday shoppers "to check something else out," said Mark Cohen, director of retail studies at Columbia Business School. FOCUS-Retailers staff up to prep for return of in-store holiday shopping FOCUS-Early Black Friday 'deals' abound, but actual bargains are scarce FOCUS-Inflation steers budget shoppers away from Walmart.