When a promotion underperforms, the post-mortem tends to start with the prize. Too small, too generic, not enough of them. Sometimes that diagnosis is right. But in our experience, the more common failure isn't any single component — it's that…

Walk any grocery aisle mid-campaign season and you'll see three or four brands running promotions at once — a prize draw here, a cashback sticker there, a gift-with-purchase two facings across. The instinct, when a rival's promotion lands, is to…