Sex and the city is of course a joke, right? Impossibly good looking women earn huge amounts of money and have great sex with a near endless number of good looking men. Some of them even fall in love and move out to the suburbs. This is simply a story, a fairy tale, no?

Well, actually, no, it looks like this could be one of the reasons that cities exist….or at least one of the ways that we use them now that they do exist.

Do people move to cities because of marriage market considerations? In cities singles can meet more potential partners than in rural areas. Singles are therefore prepared to pay a premium in terms of higher housing prices. Once married, the marriage market benefits disappear while the housing premium remains. We extend the model of Burdett and Coles (1997) with a distinction between efficient (cities) and less efficient (non-cities) search markets. One implication of the model is that singles are more likely to move from rural areas to cities while married couples are more likely to make the reverse movement. A second prediction of the model is that attractive singles benefit most from a dense market (i.e. from being choosy).

So those activities in Sex and the City seem to make sense now, don’t they? It’s especially interesting the point that it’s the best looking that benefit the most. For it is indeed the high achievers (which in the modern day means the intelligent as well as the good looking) who tend to move away to the Big City.

Imagine that you’re from Lower Podunk, a small town anywhere in the US. You are exceptional in your area: looks, skill, intelligence, whatever. You look around the potential mates in Lower Podunk and you can see that there’s no one really quite up to your standards. So, what do you do in order to get a mate up to your standards? Move to the Big city, where those high achievers from Upper, Middle, Little and Over Podunk have also moved and you end up being able to choose a mate of your quality. And the more gifted you are in any of these departments the bigger the city you’ll go to: which explains Manhattan singles bars where the Podunk Homecoming Queen wouldn’t even be let in while everyone at home thought she was beautiful.

The moving to suburbia bit also explains the bars in suburbia: after the divorce and looking for the second marriage tends to take place there.

Joking aside, the theory does explain quite a lot: most especially why people are happy, while single, to pay high prices to live in smaller homes than they could get in the suburbs.