With nearly 10 million low- and moderate-income working households paying more than half their income towards their rent or mortgage, cities are increasingly using their zoning authority to encourage the development of new workforce housing units. A study by the ULI Terwilliger Center for Housing assesses and illustrates the economics of the most common approach: inclusionary zoning (IZ). Through IZ, cities require or encourage developers to create below-market rental apartments or for-sale homes in connection with the local zoning approval of a proposed market-rate development project. This study-based on in-depth analytic modeling, an extensive literature review, and interviews with developers and other land use experts-provides such advice on what incentives work best in which development scenarios. The study's purpose is to enable policy makers to better understand how an IZ policy affects real estate development and how to use the necessary development incentives for IZ to be most effective.