When Social Scientists Fail Demography

Journalists often perpetuate demographic and geographic myths. But what if they’re interpreting academic papers correctly and it’s the experts who are to blame?

Don’t shoot the messenger. I’m hard on journalists who perpetuate demographic and geographic myths. Most of the time, journalists aren’t to blame. Tracking down the origination of brain drain claims, I find erroneous expert opinions. Letting the Washington Post (i.e. Wonkblog) off of the hook:

The below interactive map uses data from a recent working paper on happy (and unhappy) cities by economists Edward Glaeser and Oren Ziv at Harvard and Joshua Gottlieb at the University of British Columbia. Their research mines responses from the Behavioral Risk Factor Surveillance System, a national survey run by the CDC that has fueled most of what we know about the economics of happiness. …

… Many of the unhappiest cities are cities that have been in decline.

This doesn’t apply to New York, but it does to many of the other cities above: Places that have been declining in population, and that have had meager income growth, tend to have lower levels of happiness. Think St. Louis, Cleveland, Louisville. Unhappiness is particularly common in areas that have lost population. But the inverse isn’t necessarily true: Places that have been growing rapidly aren’t notably much happier. …

Did the unhappiness of these places drive people away? Or did the decline itself cause so much unhappiness? Maybe these places aren’t intrinsically unhappy at all — they just happened to attract the kind of people who were unhappy even before they moved there?

Emphasis added. Seamlessly, without concern, “declining in population” is a synonym for “places drive people away.” I see this all the time, inspiring me to write the post “Confusing Population Change With Migration.” Wonkblog is at fault if the journalists misunderstood the academic paper. But what if the experts were wrong? What if Glaeser of Harvard University confuses population change with migration? I can’t lay the common conflation at the feet of the Washington Post. Don’t shoot the messenger. From “Unhappy Cities” (PDF):

Over time, declining transport costs enabled capital and labor to flee low amenity places (Glaeser and Kohlhase, 2006) and move to “consumer cities” endowed with higher amenity levels (Glaeser, Kolko, and Saiz, 2001). Within the context of the model, this can be understood as a change in the covariance between productivity and the amenity parameters. In early 20th Century America, productivity may have been higher in lower amenity places, but in late 20th Century America, that negative covariance disappeared. As a result, population growth was faster in places that had higher amenities initially and lower levels of productivity

Emphasis added. Seamlessly, without concern, “flee low amenity places” is a synonym for “population growth was faster in places that had higher amenities.” Which brings me back to the Post and “this doesn’t apply to New York.” New York City is a place people flee (more than any other place in the entire United States)and a place with population growth. This strange juxtaposition confounds just about everyone (including me) save demographers.

Do parents in happier cities with more amenities have more sex and thus higher birth rates? If a researcher wanted to test the relationship between happiness and migration, I recommend a data set of outmigration rates instead of population numbers. I write this out of respect for other analyses such as the Federal Reserve Bank of New York, Buffalo Branch (PDF):

Upstate New York’s weak population and labor force growth in recent years has raised concerns about a loss of educated workers. Indeed, the region has seen a net outflow of college-educated people. This issue of Upstate New York At-a-Glance finds that this net outflow reflects a low rate of in-migration to the region, rather than an unusually high rate of out-migration.

Residents are not fleeing “low amenity” Buffalo. Glaeser is making an unsubstantiated assertion, misleading journalists in the process. On the other hand, we know that residents are fleeing high amenity New York City. What gives? Your move, Glaeser.

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