Wall Street follows the Dow Jones average. The Japanese watch the Nikkei. Economists study the Consumer Confidence Index. Commodity traders monitor hog futures.
At Strawbridge & Clothier, employees rely on the Christmas Party Sock Indicator (CPSI).
Here's how it works:
At the Center City store's employee Christmas party, held before the retailer opens for the day, top-ranking Strawbridge family members skip their usual conservative business black socks and deck their feet with socks of green or red. Astute observers of the CPSI can analyze the socks and figure out how the important Christmas selling season has gone.