Typically, TripAdvisor uses user reviews, like Zagat. The problem is, with any place that has a huge attendance, there are many people to give it a "5 star review" and many people to gripe and give a "1 star review". With a place like Dollywood, (and I mean no offense to anyone), the crowd that goes there is probably pretty self-selected and predisposed to love it. Me? I can't imagine stepping foot in the place. And I'm sure that there are many skeptics just like me who likewise will never go, and thus there aren't any people to drive the ratings down. To a large degree, the Universal Parks get the benefit of the same bump. There are many people who go to WDW who won't step foot in US or IOA. Thus, that lowers the population from which bad reviews can come. The people who go to US/IOA may be more predisposed to loving it. Disney, on the other hand, draws from such a wide audience that there are plenty of people who will report back that they hated it.