Are Cannes Lions Grand Prix-Winning Ads Effective? A Study Says No, Unless It's a Tide Ad

CANNES, France—Congratulations, you’ve won a Grand Prix. But is it as effective with consumers as it is with an esteemed panel of creative superstars? A study gauging the effectiveness of Cannes Lions winners may temper the elation of those taking home the biggest prize out there—the Grand Prix—but Gold winners make an impact with consumers.