Adopted by over 800 localities across the country, inclusionary zoning (also known as inclusionary housing) policies typically fall into two categories: voluntary measures that encourage the development of affordable housing by offering incentives such as increased density for the development, or mandatory programs that stipulate a percentage of units be set aside and fixed below market rents as a condition of approval for new development. Increasingly, the latter is being used by state and local governments to grow affordable housing in communities experiencing high rates of growth. While well intentioned, these policies result in the opposite outcome of it's intended aim, as they act as a tax on construction. Moreover, the incentives provided are rarely substantial enough to offset the costs imposed by set-aside requirements, and it's been shown in practice to generate little in the way of affordable housing. Mandatory inclusionary zoning is a form of rent control that stymies development and leads to overall price increases.