I don't think the ranking is completely accurate (in my opinion).. for instance, how can a pug smarter than old english sheepdog?.. pug is actually very stubborn as bulldog.. the Old English is categorized as working group, so they have used to work for human and have certain intelligence level to learn how to working for human.. I think those 獵犬 should be the smartest since they have to be smart to survive.. From what I've seen, I think big dogs are smarter than small dogs since they can learn the commands in a shorter period of time..
so I don't know how this ranking defines what "smart dog" is and based on what circumstances..