ADS PROMOTING OTC MEDICATIONS - THE EFFECT OF AD FORMAT AND CREDIBILITY ON BELIEFS, ATTITUDES, AND PURCHASE INTENTIONS

This investigation explores the effects of ad credibility and ad forma t (direct comparative vs. noncomparative) on consumers' beliefs, attit udes, and purchase intentions for over-the-counter (OTC) medications. It is hypothesized that ad credibility moderates the effects of ad for mat. 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 evid enced with higher credibility ads and with direct comparative ads. How ever, the hypothesized interaction consistently was not supported. Imp lications of these findings are discussed. (C) 1997 Elsevier Science I nc.