The Effects of Advertiser Reputation and Extremity of Advertising Claim on Advertising Effectiveness

A factorial experiment was developed in which the reputation of the advertising firm and the extremity of the advertising claim were manipulated. Two levels of advertiser reputation, focusing on the expertise and trustworthiness of the spon-soring firm, were developed. Claim extremity was structured on a rank-order scale with product claims as first, third, fifth, or twentieth best among 100 competing brands. Product evaluation was significantly influenced by both independent vari-ables and by the interaction between the two. Measures of ad credibility helped provide an explanation for the findings. W hat is the optimal level of advertising claim ex-tremity? Evidence in social psychology sug-gests that the answer to this question may depend on the level of source credibility (Aronson, Turner, and Carlsmith 1963; Bergin 1962; Bochner and Insko 1966). To date, there has been no test in marketing of the interaction of source credibility and claim ex-tremity. The present study involves a factorial experi-ment in which advertiser reputation, one aspect of source credibility, and advertising claim extremity are manipulated and the resultant level of attitude change assessed. The study also includes an assess-ment of ad credibility, hypothesized as a key media-tional variable in the change process.