The oldest quote in advertising
"Half the money I spend on advertising is wasted; the trouble is I don't know which half."
I'm a bit biased, but I have to wonder if Mr. Wanamaker gave a well-written creative brief to his advertising people. If he had, he might not have gone down in ad lore the way we remember him today.
The clearer the instructions you give to the people you hire to create your advertising, the more likely your budget will be spent wisely.
Let me re-phrase that: If your objectives are clear, if you can tell your ad agency or creative consultants what you want before you spend a nickel you'll get what you want a whole lot sooner with fewer misunderstandings and misdirection. And you'll have advertising whose results you can measure.
You'll have ROI you can count on.
From one piece of paper?
Yes, if it's written with authority and inspiration, backed by research and consumer insights, and benefits that are relevant to the audience you're selling to.
Look at it this way: If you take a trip across the country and the map you use to make your way is inaccurate and out of date, what happens? You get lost.
Why would you expect anything different if the instructions you give (or allow to be given in your name) to your ad people are just as faulty? Or don't align with your brand?
A well-written creative brief is your insurance policy.
A well-written creative brief puts you in control of the trip you're sending your advertising people on.
A well-written creative brief puts your advertising budget on a more direct path to being spent wisely.
It's your money. Start by spending it on a finely honed document that gives crystal-clear instructions.