This data will have many applications. In earlier versions, scholars used the data as a proxy for economic development — see for example the case of North and South Korea at night.
Continuing declines in air pollution are linked to increasing life expectancy, a national study has found…
…The study, published online last week in the journal Epidemiology, used data from 545 counties nationwide, both metropolitan and rural, and found an average decrease of 1.56 micrograms per cubic meter in particulate pollution over the eight years. At the same time, life expectancy increased an average of 0.84 years.
Of course, many other factors contribute to increased life span besides cleaner air. The researchers controlled for smoking prevalence, income and other health and economic factors. They estimated that about 18 percent of the increase in life span can be attributed to reduced air pollution.
The border is also a window into the future. Profound shifts in economics, demographics and crime are transforming immigration patterns and causing upheaval in Central and North America. After decades in which Mexicans dominated illegal immigration to the United States, the overall number of immigrants has dropped and the profile has changed.
Although Mexicans remain the largest group, U.S.-bound migrants today are increasingly likely to be young Central Americans fleeing violence as well as poverty, or migrants from remote locales such as India and Africa who pay top smuggling fees. They journey through a gantlet of predators.
Those lagging scores have real-world consequences, says Eric Hanushek, a Stanford economist who was one of the first to rank American students against their foreign counterparts. “If you look across nations over the last 50 years, the growth rates are really very highly correlated with math performance on these basic tests,” Hanushek says.
[T]he most interesting findings from our paper are that (1) the effect of density on productivity is practically zero (or even negative) in low-human capital metros, but the effect of density on productivity is quite substantial in metros with high college attainment shares; and (2) the interaction effects of population density and college attainment on productivity are highest for the industrial sectors of information, finance, arts and entertainment, and professional services—sectors that place a high premium on creativity and sharing of ideas.