Measuring Exposure to Political Advertising in Surveys

Abstract

Research on the influence of negative political advertising in America is characterized by fundamentally conflicting findings. In recent years, however, survey research using estimates of exposure based on a combination of self-reported television viewing habits and Campaign Media Analysis Group data (a database of all advertisements broadcast on national and cable television in the top 75 media markets) has argued that exposure to negative political advertising boosts interest in the campaign and turnout. This paper examines the measurement properties of self-reports of television viewing. I argue that the errors from common survey formats may both be nonrandom and larger than previously acknowledged. The nonrandom error is due to the tendency of politically knowledgeable individuals to be more sensitive to question format. Thus the inferences drawn about the relationship between political knowledge, exposure to negative ads, and political behavior are also sensitive to the measures used to estimate exposure. I demonstrate, however, that one commonly used measure of exposure—the log of estimated exposure—is not only more theoretically defensible but also alleviates some of the more serious problems due to measurement error.