Measuring the Results of an Ad, Right Down to the City Block

The people who buy media have found their jobs more complicated lately, what with all the new ways of measuring response — how many people clicked, clipped a coupon or made a purchase after seeing an ad. Buying local media adds another layer of complication. There are newspapers, billboards, Sunday circulars (those coupon-laden pages stuffed in the weekend paper), Yellow Pages and mail-based coupons. And they exist in hundreds of towns coast to coast where a marketer might have stores or products. Mediabrands, an ad-buying and planning division of the Interpublic Group, plans to introduce a unit on Thursday, Geomentum, that will focus on this problem. Geomentum will be large, handling about $2 billion a year in local advertising for companies like Coldwell Banker and Nestlé Waters. It will figure out how to divide ad dollars among the almost 40,000 ZIP codes in the United States, sometimes zeroing in on even smaller areas, like a city block.