Three years ago, I made a decision to move from New York City to Madison, WI based purely on research. I put economic development research together with positive psychology research. Then I combed the Internet for city statistics, and I moved. (If you want to read the research I used, I linked to it all in this post.)

I had never been to Madison in my life, and you know what? It was a good decision. Except for one thing: I ignored the data about schools. I didn't believe that a city known for progressive social programs and university filled with genius faculty could have poorly performing public schools. But it ended up being true, and all economic development research says do not move to a place with crap schools—it's a sign that lots of things in the city are not right.

So when you decide where to live, pay attention to the research. Ignore stuff like the geography of personality because it's interesting, but there's no data that says it correlates to what makes you happy. And pay attention to research that flies in the face of everything you know, like you can be a millionaire anywhere. But, then, you should probably not be looking at that research because being a millionaire won't impact your happiness so it should not impact where you choose to live.

Here's some research I've found recently that you should consider if you're considering relocating:

Live by water.
People who live inland are not as happy as people who live near water, according to research coming out in the American Journal of Preventative Medicine. And some scientists think this is because humans evolved by following the shorelines and living off water life. So, the Journal of Preventative Medicine shows that if you live in the Appalachian Mountains you are twice as likely to have mental illness than if you live in Hawaii.

Live where people have as much money as you do.
Of course, the Hawaii vs. Appalachia issue is clouded by the overwhelming evidence that people have a lot more money in Hawaii. It's true that money does not buy happiness. But it is only true if you are not living in poverty. Poverty is pervasive in Appalachia, so that probably accounts for a lot of the mental health problems there. But don't go move somewhere where everyone's got a lot of money, because financial security is relative. And you need to have a little more money than your friends do in order to feel financially secure.

Move to where your friends are.
If you move within a mile of a good friend, both of you will become significantly happier, according to Nicholas Christakis, a physician and sociologist at Harvard. If you're considering relocating away from friends and family because you believe money will buy happiness, you are sort of right. But Nattavudh Powdthavee of the University of London shows that you'd need to have a salary increase of at least $133,000 in order to have a net positive impact on your happiness from that move.

Move to an inexpensive city if you want to start a company.
Seventy percent of Gen Y wants to start a company. So a lot of people are relocating to do that. You might think you need to be in Silicon Valley since the people there never shut up about their startup culture. But in fact, most startups need to keep their burn rate low more than they need that mythic startup culture, so you should move to a city with a low cost of living.

Maybe you should stay where you are.
When one spouse relocates for another, they generally end up earning less over their career because of it. So maybe spouses should stop relocating, period. There is a widespread feeling among Generation Y that transience is exhausting, and relocating away from family and friends for a job is a nonstarter. And anyway, it used to be that you could get a company to pay for your relocation, but Microsoft just announced it is no longer doing that, and you can bet other companies will follow.

So at some point, relocation starts looking expensive, high risk, and maybe a bad idea. Unless you're starting from New York City.