Recent decades have witnessed some evolution in both the focus of and the approaches to urban housing policy. Certain housing problems have seen some resolution, and other issues remain at the forefront of the national policy debate. Some improvement has been recorded in the physical characteristics of the housing stock, overall housing conditions, and problems of residential overcrowding. However, the limited availability of affordable rental units, mortgage f1nance—related constraints on homeownership, reduced housing and income assistance to very low income populations, problems of public housing and low-income housing preservation, and issues of equal opportunity in housing and housing finance markets remain at the forefront of the current housing policy debate.

By various measures, the adequacy of the nation’s housing stock has registered significant improvement since World War II. For example, more than 40 percent of U.S. housing units were without complete plumbing facilities at the end of World War II; by 1980, such units had fallen to less than 1 percent of the U.S.  housing stock.1 According to the 1990 decennial census, approximately two-thirds of the U.S. housing stock was single-family units; the vast majority of homeowners lived in single-family units. In contrast, housing units in structures with four or more stories constituted only about 10 percent of all existing housing units. Census data indicate that some 16 million single- and multifamily units were added to the housing stock over the 1980s at an average pace of 1.7 million units per year. The average size of those newly constructed units increased by over one-fifth, from 1,720 to 2,080 square feet.