Are there as many rats as people in New York City?

Urban legend states that New York City has as many rats as people: roughly 8 million; but a new analysis suggests there are nowhere near as many.

The analysis classified rat sightings by city lot, of which there are roughly 842,000 in New York City. The researchers estimated 40,500 rat-inhabited lots in the city. By liberally assuming that 40 to 50 rats belong to a typical colony and that one full colony occupies each rat-inhabited lot, the researchers concluded that 2 million would be an extremely generous estimate of the city's rat population.

"While the rat population remains a serious problem in New York City, there appears to be no evidence supporting the 8 million number. In problems like this, the city's open data is invaluable for challenging rumors, evaluating community need and establishing government efficacy," said Jonathan Auerbach, author of the Significance study winner of the YSS/Significance Young Statisticians Writing Competition.