Not so helpful after all.
What’s the News: City lights are more than a pretty sight from the air—they’re also a good way to tell how a country’s economy is doing, some economists say. Over the past decade, deducing a country’s gross domestic product from how much it glows in nighttime satellite images, a factor called luminosity, has become quite the econ fad. But as clever as it sounds, luminosity isn’t as helpful as you’d think, a new study says. Only in countries that are such a disaster that gathering reliable statistics is impossible is the glow a better approximation of GDP than you’d get with traditional measures.