Featured by the Wall Street Journal. 

Four percent of Manhattanites go to bed before 7:30 p.m. on weeknights. Only 6% turn off the lights after midnight.

For more fine-grained data on what makes New York City tick, ask researcher Steven Koonin. Hidden on a Brooklyn rooftop, his wide-angle infrared camera peers at windows of thousands of buildings across the East River. The camera detects 800 gradations of light, a sensitivity that lets his software determine what time households turn in, what kind of light bulbs they use, and even what pollutants their buildings emit.

He has also mounted sound sensors in Brooklyn on streetlight poles and building facades to gauge the volume of house parties and car horns.

Mr. Koonin, a former undersecretary of science in the Obama administration who directs New York University’s Center for Urban Science and Progress, is at the forefront of an academic movement to quantify urban life.

Tech companies have used the technologies and techniques collectively known as big data to make business decisions and shape their customers’ experience. Now researchers are bringing big data into the public sphere, aiming to improve quality of life, save money, and understand cities in ways that weren’t possible only a few years ago.