How many exposures does an ad need to be effective? And in what period of time? No one knows for sure. Another way of putting it is: is there a minimum threshold of media weight needed to make an ad campaign work? The answer seems to be 'yes'.1
I once saw a new campaign come very close to being cancelled by the client. A whole battery of effectiveness-tracking measures said the campaign was having a disappointing and marginal impact. The client was close to the point of concluding that the ads were 'hopeless'.
The media weight for this campaign was around 150 TRPs per week. This means that the people who were the target market for the product were supposed to be exposed to it on average about 1.5 times a week.2 At least that was what was planned. Before labeling any campaign a failure or concluding that 'these ads don't work' it is crucial to look at the actual TRP figures, the actual delivered, as distinct from the planned, media weight.
Sometimes ads do not go to air because of some mix-up. Sometimes the buying of air time is not as good as it should be. Sometimes (as in the changeover to daylight saving, holiday periods, etc) there are not as many people watching TV as there were the previous week. In this example, when these actual TRP figures were obtained (some two months after the campaign had started), it emerged that only about 60 per cent of the planned weight was in fact achieved (i.e. about 90 TRPs per week).
Corrective action was taken and in the subsequent weeks the planned exposure rate, the full 150 TRPs per week, was achieved. With this weight the campaign went on to perform amazingly well in the test market and later nationally. The reason the campaign was not working originally had