"Half the money I spend on advertising is wasted; the trouble is I don't know which half"
John Wannamaker said that in the 1800's and yet most businesses still aren't measuring their marketing today.
Advertising agencies are very happy to measure anything but results. Agencies distract their clients with irrelevant numbers and silly jargon. What answer do you get when you simply ask how much business an ad will bring in? Usually no answer at all, or something like "It's not really about that, this advert will build awareness" or worse still "We're helping you tell a story, don't worry about ROI, this is much more than that"...
What a load of nonsense.
You need serious, effective marketing to help your business. Attract more of the right customers. Attract fewer bad customers. Keep the good customers for longer. And build customer value by adding new sources of income.