Today's chief marketing officers (CMOs) confront a painful reality: their traditional marketing model is being challenged, and they can foresee a day when it will no longer work.

The declining effectiveness of mass advertising is only the most visible sign of distress. Marketers also face a general proliferation of media and distribution channels,¹ declining trust in advertising, multitasking by consumers, and digital technologies that give users more control over their media time.² These trends are simultaneously fragmenting both audiences and the channels needed to reach them. The danger for marketers is that change will render the time-honored way of getting messages to consumers through TV commercials less effective at best and a waste of time and money at worst.

Among marketers, there's much frustration and little agreement about what to do next. Some are reaching for marketing-mix models that use sophisticated econometric methods to tease out the different effects of the marketing mix on business results (see sidebar, "Beware the quantitative cure-all"). But the historical data that fuel such techniques may prove an unreliable guide to future returns.

Marketers need a more rigorous approach to a fragmenting world¡ªone that jettisons mentalities and behavior from advertising's golden...