As you might already know, the question of measurement is yet to be answered in the field of nation/place branding. There are a couple of commercial measurement scales such as The Anholt-GfK Roper Nation Brands Index, and FutureBrand’s Country Brand Index. There are also several academic studies (examples can be found here and here) that work on conceptualizing place brand measurement scales. I have a long-term research project I still work on entitled “Define-Measure-Visualize“.
Recently, I was introduced to the Country Brand Ranking created by Bloom Consulting. Unlike the other commercial products, CBR focuses on facts and figures through international agencies, and look at the branding messages to rank countries.