An upwardly biased random walk? Don't we expect stock markets to go up as wealth is created?
That's the crux, isn't it? How do you know if an upward trend line is irrationality or wealth creation?
If you want to measure how close areas are to a competitive market, I would suggest looking at profit margins in non-monopolistic industries. Of course, you'd have to control for regulatory differences and relative concentrations of different industries. But, all else being equal, the place where profits are higher is farther from being a competitive market.
Are certain areas of the world, specifically within the United States, more or less rational than others? If so, which ones and why? I am trying to determine what parts of the country would be ideal for me to live in the future and any help would be greatly appreciated.