Constantly measuring the advertising success of a campaign and deciding the relative importance of the individual influences is a complicated task in view of the large number of variable influences, usually acting simultaneously, which are encountered in the course of the campaign (e. g, competitors' activities, simultaneous advertising in different media, etc.). However, it is even more difficult to take the results of such analysis and embody them quickly and to the best advantage in further planning. The paper shows the practical application of a system of interviewing by means of which the weightings of the various influences in an advertising campaign can be determined and calculated. Integration in a mathematical multi-media optimisation program ensures that the results obtained can be utilised as quickly as possible in planning the subsequent course of the campaign. Advertising research thus becomes a firm part of media planning.