The U.S. Department of Housing and Urban Development (HUD) is pleased totransmit to the U.S. Congress this 2017 report on Worst Case Housing Needs.This report-the 16th in a longstanding series-provides national data andanalysis of the critical problems facing low-income renting families. The reportdraws on data from the American Housing Survey (AHS), which is funded by HUDand conducted by the U.S. Census Bureau. The AHS has been conducted every2 years since 1973 and debuted a major redesign in 2015 that included a newnational and metropolitan area longitudinal sample. The AHS is a key source ofnational data on housing markets, conditions, and dynamics.Despite continued signs of a strengthening national economy, the report findsthat severe housing problems are on the rise. In 2015, 8.30 million householdshad worst case needs, up from 7.72 million in 2013 and approaching the recordhigh of 8.48 million in 2011. These households are defined as very low-incomerenters who do not receive government housing assistance and who paid morethan one-half of their income for rent, lived in severely inadequate conditions, or both. High rents in proportion to renter incomes remain dominant amonghouseholds with worst case needs, leaving these renters with substantial, unmetneed for affordable housing.The modest reduction in worst case needs observed in 2013 was not sustainedand worst case needs continued their upward trend. Specifically, severe housingproblems have grown 41 percent since the beginning of the Great Recessionin 2007 and 66 percent since 2001. Worst case needs continue to affect allsubgroups, whether defined by race and ethnicity, household structure, or locationwithin metropolitan areas or regions.Contributing most to the increase in worst case needs between 2013 and 2015was a notable shift from homeownership to renting. The magnitude of thissustained postrecession trend, along with other demographic factors, increasedthe number of very low-income renters and thereby played a major role in growingworst case needs between 2013 and 2015. Modest gains in household incomeswere met with rising rents, shrinking the supply of affordable rental housing stockin an increasingly competitive market. Even with the supply of more expensive unitsgrowing, higher-income renters occupy a growing share-43 percent-of the mostaffordable units. Only 62 affordable units are available per 100 very low-incomerenters, and only 38 units are available per 100 extremely low-income renters.This report also uses new AHS enhancements to explore the variation in worstcase needs and the distribution of housing assistance across a greater variety ofmarket geographies. These data show that, although 43.2 percent of very lowincomerenters had worst case needs nationally, local markets reflect a substantialdegree of variation beyond the longstanding trends observed across regions andtypes of metropolitan location