Testing may occur at various points throughout the development of an ad or ad campaign. It is important that marketers understand each of the four major steps of the process, as well as key output that is needed in each phase to measure the effectiveness of the ad or campaign. The marketer must put the four steps of the process in order, and then match them with the appropriate output desired at each step. All marketing managers want to know how well their promotional programs are working. This information is critical to planning for the next period, since program adjustments and/or maintenance are based on evaluation of current strategies. Problems often result when the measures taken to determine such effects are inaccurate or improperly used. Assessing the effectiveness of ads both before they are implemented and after the final versions have been completed and fielded offers a number of advantages