One of the most apparent applications of the knowledge gleaned from Effects Theory would be to the area of copy testing. When advertising is hanging is to be presented to an audience and researchers are determining if a message is persuasive or not, many of the contributing persuasive factors presented in Effects Theory are suggestive of certain expected results.
For example, an ad may simply be too vague without a complete conclusion drawn by the concept of the ad. Or a fear appeal may seem to strong to be believable. Do you want to die a fiery death? may not be the best headline for an automatic shutoff iron.
This brings up an additional insight. Creatives must be in tune to the effects of the messages they are creating. The target audience is often cited to determine the acceptable language, culture, and style, but the characteristics of the audience (particularly their level of education) could be quite indicative of the type of message that will ultimately be persuasive.
Furthermore, the media planner must consider the source an ad will be found in. The New York Times carries more clout than a local-weekly paper for most individuals. Again the composition of the receiver will be important.