Part of that has to do with people learning about the risk factors. Maybe they didn’t know the area they’re living in is so susceptible to storms.
Part of it is watching whether the existing infrastructure really works.There’s discussions now about Houston not really having enough of a drainage system. People might have known, yes, there are tropical storms, but they may not have understood the tropical storm is going to be such a devastating effect.
Zhang: Like when levees broke during Katrina.
Boustan: Yes, does the bayou hold or does the floodwall to seawall hold? You can observe another city going through it but then it may not be salient until it actually happens to you.
Zhang: The Gulf Coast is obviously pretty prone to hurricanes, so it’s not surprising that a big one would eventually hit Houston. Do people in disaster-prone areas respond differently than those in places that don’t get hit as often?
Boustan: The results there are really striking. We use some of the geography for different areas to say what the characteristics are of an area that make it susceptible—if you’re on the coast, if you’re in the Gulf of Mexico, if you’re along a major river, if you’re at a low elevation. And it’s precisely in the places in the path of regular disasters that, when there’s a really big disaster, people tend to start to pack it in and leave.
That was sort of puzzling to us as economists—an economist being the type of person who’s like, “Shouldn’t people be able to gather information and assess risk and make these decisions, like looking a spreadsheet?” There’s new information coming when it’s a surprise: You’re not expecting a disaster at all, and you haven’t had the experience of stocking up your house and getting the candles and getting the food ready. [You might think that] people who are in the wake of disasters might know how to respond and it’s not really that surprising. But that doesn't seem to be the case.
Zhang: You usually study migration in a more general context. How did you get interested in specifically looking at natural disasters?
Boustan: I’ve worked on the black migration from the rural South to industrial cities during and after World War II, and one of the theories in that literature is that the migration out of the South began in part in response to a devastating flood in 1927 of the Mississippi River.
Zhang: The years you studied, 1920 until 2010, cover a pretty long period, including a lot of changes in how the government responds to disaster. How has the government stepping in affected how people react to, say, a hurricane?
Boustan: In the 1920s and 1930s, the federal government kind of contracted out the disaster response to the Red Cross. It’s not quite fair to say that it was a completely private response to disasters at the time, dependent on only private donations, but there wasn’t the same kind of government infrastructure like FEMA [the Federal Emergency Management Agency] that we’re used to today.