Finding the Cost of Campaign Advertising∗

Debates about campaign finance often point to television advertising as a major reason for the high cost of campaigning, but the debates are too rarely informed by systematic data on advertising costs. A leading source tracking campaign ads, the Campaign Media Analysis Group (CMAG), offers data about both the volume and the estimated cost of advertising being purchased. Here, we test the accuracy of CMAG cost data by comparing CMAG estimates to records we gathered directly from television stations for five competitive campaigns in the Philadelphia area in 2006. Our findings show that while CMAG is highly accurate in gauging the incidence of advertising, CMAG estimates of the cost were much higher than the actual cost. We counsel caution then in judging the cost of television advertising based on CMAG estimates