Exactly branding was our marketing department go-to excuse for ROI negative campaigns. We ended up trying to measure the branding by tracking users who came to

Exactly branding was our marketing department go-to excuse for ROI negative campaigns. We ended up trying to measure the branding by tracking users who came to our site directly by typing the url into the address bar, or who googled our website by name, so we can estimate how strong the branding was. The only problem is you can't really do this on a per campaign basis, but if you geo target your campaigns and check the brand strength stats on the same geo targets you can get a rough estimate.