In this corner of demographic analysis, wunderkind Nate Silver takes on popular opinion about why Eric Cantor lost a Republican primary in Virginia. In the other corner, Matthew Yglesias maps demographic doom. To be fair, Yglesias isn't trying to out-Silver Nate Silver. Nonetheless, Yglesias manages to obfuscate where Silver illuminates:
Indeed, there’s robust evidence that politics are becoming more nationalized; state and local races (like those for governor) are more likely to follow patterns from federal races and less likely to involve ticket-splitting.
But it’s less clear that this has much to do with migration patterns, or at least not in the way that The New York Times proposes. More of the evidence contradicts rather than supports its hypothesis, in fact.
The theory doesn’t align well with the results in Virginia. If migration to Virginia was a major contributor to Cantor’s defeat, you’d expect Cantor to have done worse in counties where there were more transplants.
Silver takes a theory that rings true and runs it through the wringer with a simple natural experiment. For something in the popular press, Silver provides a good stab at debunking a demographic stereotype. As for Yglesias, he passes along the tired geographic stereotype of dying communities with "The 25 Cities Nobody Wants to Live In":
Each year more Americans are born than die, and more people move here from abroad than emigrate to foreign countries. So most municipalities see their populations grow. If you're shrinking, something is really going wrong. ...
... Population shrinkage can be a big problem for cities since there's always a risk of setting off a self-reinforcing trend. A given municipality is bound to have a fair number of fixed costs (pensions, upkeep on roads and government buildings) that don't scale down when the population shrinks. That leaves the remaining population to either suffer higher taxes or reduced levels of public services, either of which further encourage population flight.
I imagine Nate Silver would read that and wonder, "Does demographic decline really catalyze more outmigration?" I doubt Yglesias knows for sure whether or not it is true (it isn't). He wrote it anyway because that's what most people think. Ezra Klein lays out the raison d'être for Vox:
Early last year, Melissa Bell, Matt Yglesias and I began wrestling with a question that had bugged all of us for a long time: why hadn't the Internet made the news better at delivering crucial context alongside new information?
In his blog post about shrinking cities, Yglesias fails to deliver any context alongside new information (Census data). Instead, he misrepresents what the numbers indicate and the reader is much the poorer for it. This kind of contribution doesn't make news "better." It makes it worse, journalism in retrograde. Uncritical assumptions are running amok.
"A given municipality is bound to have a fair number of fixed costs (pensions, upkeep on roads and government buildings) that don't scale down when the population shrinks." Just because the population is shrinking doesn't mean revenue is shrinking. The same number of households are occupied, but the adults had fewer children. Women with college degrees generally have fewer children while the households earn greater income. Fewer dependents with a bigger and better educated workforce is a fiscal win for any city. That's the crucial context missing from this bit of news. Some of the population winners are the real losers (more elderly dependents on fixed incomes) and some of the population losers are the real winners.