Good planning and control of advertising depend critically on measures of advertising effectiveness. Most advertisers try to measure the communication effect of an ad, that is, its potential effect on awareness, knowledge or performance.

Communication effect reaches seeks to determine whether an ad is communicating effectively. Called copy testing, it can be done before an ad is put into media and after it is printed or broadcast.

There are three major method of advertising pre testing. The first is the direct rating method, which asks consumers to rate alternative ads. The second is portfolio tests which asks consumers to view and/or listen to a portfolio of advertisements, taking as much time as they need. Consumers are then asked to recall all the ads and their contents, aided or unaided by the interview. The third is laboratory tests which use equipment to measure consumers physiological reactions- heat beat, blood pressure, pupil dilation, perspiration-to an ad.