Jane Jacobs, a woman akin to the patron saint of urban planners, first argued 50 years ago that healthy neighborhoods need old buildings. Aging, creaky, faded, “charming” buildings. Retired couples and young families need the cheap rent they promise. Small businesses need the cramped offices they contain. Streets need the diversity created not just when different people coexist, but when buildings of varying vintage do, too.
“Cities need old buildings so badly,” Jacobs wrote in her classic “The Death and Life of Great American Cities,” “it is probably impossible for vigorous streets and districts to grow without them.”
Ever since, this idea — based on the intuition of a woman who was surveying her own New York Greenwich Village neighborhood — has been received wisdom among planners and urban theorists. But what happens when we look at the data?