If we are leveling our critical analysis and skepticism to the extreme I would say that all these studies are never settled and the World Happiness Report does not invalidate findings of the other study.

> there is a trend which suggests Americans are growing less happy each year. So maybe in the interim of 4 years the world.

So are you saying that Amricans = World? Please (for example) go to Spain and look about how happiness works differently than America.