Definition of reason-why advertising

copywriting approach to print advertising whose format is to state a fact about a product or service in a headline and then explain why the fact is true in the copy text. The idea behind this type of advertising approach is to give a reason why a customer should buy the product or service. Reason-why advertising works better in print than in broadcast, because the reader has more time to consider the message. Broadcast presents a time limitation, and the viewer may very well miss the opening headline or the reasons why the opening headline is true.