In 1961, the New York City Planning Commission passed an incentive Zoning Resolution enabling private developers to build taller or denser buildings in exchange for providing public space. In was a pioneering attempt to regulate urban form and enhance the public realm. But the privately owned public spaces (POPS) that have emerged during the past four decades, while adding significantly to the quantity of public space in the city, are decidedly mixed in terms of quality and accessibility. This study aims to shed more light on how accessible, active, and desirable these POPS really are.