Many product and service categories feel like this year’s crop of Republican candidates — too many brand choices with only a few standing out either from past reputation, the ability to shout louder or making a noticeable faux pas. It is increasingly hard for brand marketers to break through in a motivating way, even with what should be a winning brand proposition.

In analyzing thousands of ad campaigns and execution test processes, the single biggest factor is simple to diagnose, but hard to fix — great ads come from a really strong, tight creative brief. Brilliant ideas, duds or boringly average campaigns — there is a high correlation between these outcomes and how strong the brief was.

Poor creative is too often the function of a vague or broad brief that leaves the agency up to its own imagination about what the customer is thinking and where the brand fits into consumers’ lives. As Chuck Cooper, the former CEO of Helene Curtis who pushed the brand past P&G for the No. 1 position in hair care, always preached, “Well begun is halfway done,” and this is especially true when it comes to developing a creative brief.