Advertising agencies struggle. They struggle to prove their worth for the limited resource marketing directors have at their disposal. Marketing directors, too, are demanding more transparency and are expected to prove the effectiveness of the advertising spend to the purse-string holders. The advertising community has responded by compiling myriad techniques designed to justify adspend and the resource invested in its skills. Some of these techniques are spurious bamboozlements, but some work. None, however, addresses one critical factor: how to quantify advertising's contribution to brand and business value.

With the trend for transparency...