Donny and Kaisy had just flown in from the U.S. and were being chauffeured to their Bologna hotel when Donny suddenly told their driver to stop. Kaisy looked puzzled as well as jetlagged. "No point in arguing abstractions," Donny said, throwing open the car door. "I'm going to show you what I mean about the value of the 18-to-49 demographic."

He and Kaisy had spent most of their flight debating how to approach a new American marketing campaign for their employer, Fiero, an Italian stove maker. Kaisy, a tech-savvy 26-year-old, was advocating a whole new approach to understanding consumers. A vendor named Settop Analytics could harvest household TV-viewing data from the cable companies and cross-match it with survey findings and credit-card information from merchants to tell Fiero that, for example, 4% of the viewers of a Fiero ad on the show Modern Life are in the market for a stove, compared with just 2% of the viewers of America's Got Brains, even though both have about the same 18-to-49 rating.

To read the original article: Does the 18-to-49 Demographic Matter Anymore? An HBR Management Puzzle - Horst Stipp and Jeffrey McCall - Harvard Business Review