Audience measurement : Dysfunction due to the lags...

Surveys of radio audiences and the press are conducted four or five times a year in most countries. The data are provided with a processing time of several weeks. However, most of these media campaigns that use no more than three weeks. How could - justify the quality of the space that we sell to buyers whom we could not provide information on the effectiveness of our media campaigns for several months after? Some advertisers are forced to drive further action against them to adjust their campaigns. Why?