Arguments can be persuasive without being believable. Good research will help you determine whether your argument is both.
The worst trap you can wander into is betting the farm on an argument that research shows is persuasive, but fails to probe deeper to see whether it is believable.
Several years ago, we conducted quantitative research to test the best arguments for a state transportation funding package. The argument that proved most persuasive was the list of transportation projects contained in the legislation to be funded. People liked knowing what the increased gas tax money would pay for.
However, probing deeper revealed that many of the people who liked the idea of a specific list of transportation projects believed that they never would be built. The list was persuasive, but they doubted the credibility of the state agency to follow through.
When the transportation funding bill went to the voters, it was soundly thrashed. Exit polling underscored the problem — a persuasive argument wasn't credible enough to carry the day.
The questions of persuasiveness and believability don't just apply to public policy issues and campaigns. They also are meaningful in a marketing context. A product feature may appeal to potential customers, but unless it convinces them to buy, it is just a nice feature — appealing, but not put-it-in-my-shopping-cart convincing.