On second thought, leave the lights on

The glow of lights in a city at night means different things to different people. For some, the amazing hues along Broadway, the Las Vegas Strip or the Sunset Strip in Hollywood mean a fun night out. For an economist, these dazzling lights signify people's pockets are flush with cash; and in fact, a new study confirms it. Research by William Nordhaus, Sterling Professor of Economics at Yale University and Quinnipiac University sociologist Xi Chen shows nighttime lights, when seen from outer space, reveal how economically developed an area is. For a place like the United States that has strong data collection programs, the radiance of nighttime lights corroborates measures of economic activity, such as gross domestic product (GDP). But for other places that do not have strong data collection programs--some countries in Africa, for example--nighttime lights only have limited use.