Persuasion shift testing

Andy Farr

The use of 'pre-post' shift in pre-testing advertising has varied in popularity since it was first introduced in the late 1950s. Attempts to refine these techniques by RBL in 1972-73 will also be recalled. Now it seems to be coming back into vogue.

This paper discusses a major experiment undertaken to understand the pre-post persuasion shift pre-testing technique widely used in the US and now being offered in the UK. The paper demonstrates that persuasion is predominantly driven by the existence of new information, and that the technique's results can be largely replicated via sensitive introspective questions. The author concludes that this puts immediate persuasion back into perspective as one interesting and sometimes useful number. But it represents only part of any evaluation, its relevance depending upon the strategic goals of the advertisers.