Recruiting a former Baywatch star to hand out free potato chips and beer may sound like a cheap publicity stunt, but for one British brand, it actually helped boost sales.

Judges at a major award ceremony for the advertising industry in France this weekend evaluated marketing campaigns for the first time on how much product they sold, not just whether they made people laugh, cry or cringe.

The grand-prize winner, a U.K. campaign for Walkers potato chips, brought Pamela Anderson and other celebrities into the British town of Sandwich, Kent, to illustrate the tagline, "Walkers can make any sandwich more exciting."

The new prize for effectiveness, handed out Saturday at the Cannes Lions International Festival of Creativity, signals a shift toward greater accountability for ads.

To win in the effectiveness category, an ad had to show a proven impact on "consumer behavior, brand equity, sales, and, where identifiable, profit." Judges combed through more than 150 entries.