Ads promoting OTC medications: The effect of ad format and credibility on beliefs, attitudes, and purchase intentions
通过三个实验研究广告可信度和格式（直接比较vs非比较）如何影响消费者对非处方药的信念、态度和购买意向，发现高可信度和直接比较广告更能说服消费者。
This investigation explores the effects of ad credibility and ad format (direct comparative vs. noncomparative) on consumers' beliefs, attitudes, and purchase intentions for over-the-counter (OTC) medications. It is hypothesized that ad credibility moderates the effects of ad format. To test the hypotheses three different experiments were conducted, with each one using a different method to manipulate ad credibility (multiple explanations for claimed superiority, claim substantiation, and approval of ad information from the Federal Trade Commission). The results of the three studies provide consistent support for the main effects of ad credibility and ad format. Increased persuasion was evidenced with higher credibility ads and with direct comparative ads. However, the hypothesized interaction consistently was not supported. Implications of these findings are discussed.