March 2008
In this Issue
Is a Concept Home in Your Future?
Home Lighting and Appliance Efficiencies
Subprime Mortgage Woes May Spur Changes in AHS Data
Measuring Overcrowding in Housing
In the next issue of ResearchWorks
Measuring Overcrowding in Housing
Overcrowding in housing threatens public health and safety, strains public infrastructure, and points to an increasing need for affordable housing. The Centers for Disease Control and Prevention (CDC) says housing is safe and healthy only when it meets the basic physical and psychological needs of its inhabitants, which include sufficient living space to minimize the spread of contagious illnesses and meet the need for privacy. The Healthy Housing Reference Manual, developed by CDC and HUD, states:
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Ideally, everyone would have their own rooms, or, if that were not possible, would share a bedroom with only one person of the same sex, excepting married couples and small children. Psychiatrists consider it important for children older than 2 years to have bedrooms separate from their parents. In addition, bedrooms and bathrooms should be accessible directly from halls or living rooms and not through other bedrooms. In addition to the psychological value of privacy, repeated studies have shown that lack of space and quiet due to crowding can lead to poor school performance in children.
The amount of living space required to meet health and safety standards is not consistently specified; measurable standards for overcrowding vary. The most widely used measure assumes that a home becomes unhealthy and unsafe when there are more than 1, or sometimes 1.5, household members per room (PPR). Another frequently used measure is the number of individuals per bedroom, with a standard of no more than 2 persons per bedroom (PPB). Assisted housing programs usually apply this standard. Yet another method measures unit square footage per person (USFPP), which quantifies the amount of personal space available to each inhabitant.
Measures Compared
Measuring Overcrowding in Housing, recently released by HUD's Office of Policy Development and Research, is part of a broader exploration of the many ways in which the biennial American Housing Survey (AHS) can serve the housing research community. This study uses AHS data from 1985 to 2005 to compare outcomes when different measures of overcrowding are applied to the same data.
The AHS defines a room as an enclosed space used for living purposes, such as a bedroom, living or dining room, kitchen, recreation room, or another finished room suitable for year-round use. Excluded are bathrooms, laundry rooms, utility rooms, pantries, and unfinished areas. Room size is generally determined by custom and building codes. Under the PPR standard of more than one person per room, the AHS data indicate a low level of overcrowding, with the rate falling from 2.8 percent of American households in 1985 to 2.4 percent in 2005. The PPB standard also fell but showed a slightly higher level of overcrowding; the incidence rate of more than 2 persons per bedroom was 3.25 percent in 1985 and 2.65 percent in 2005. Principles of health and privacy might make this the measure of choice, due to the effects of human proximity on infection, airborne disease, and personal privacy. When a USFPP minimum standard of 165 square feet was applied, overcrowding declined from 3 percent in 1985 to 2.4 percent in 2005. This measure is also an indicator of the amount of personal space available and is useful in illustrating how the average house size changes over time.
In a demographic analysis of AHS data, investigators looked for differences and trends in overcrowding among demographic groups, segmented by ethnicity and race, citizenship, income, owner or renter status, region, and metropolitan area. This analysis suggests that overcrowding may be somewhat under- or overestimated among subpopulations, depending on the measure applied. Although the results varied slightly, all three measures pointed to higher rates of overcrowding among Hispanics, renters, foreign-born noncitizens, Westerners, lower-income families, and central city dwellers.
Discussion
A number of factors may contribute to the overall decrease in the incidence of overcrowding in the past two decades. As living standards improved and mortgage financing became more accessible, more Americans were able to buy or upgrade their homes. In addition, as homeownership rates rose, the average home size expanded while the average household size grew smaller. One explanation might be that contemporary homebuyers are planning further into the future, buying more space now that will accommodate a growing family later. Another influence is the sizeable cohort of aging Americans who are still healthy and active. Many remain in the "empty nests" in which their families grew up, essentially becoming overhoused. Finally, researchers note, perceptions of the function of a particular room may have evolved, requiring additional living space.By raising these questions, Measuring Overcrowding in Housing (available at www.huduser.gov/ publications/polleg/overcrowding_hsg.html) demonstrates an interesting application of the AHS while revealing several research opportunities that can be applied to the planning and development of safe, healthy, and affordable homes. Interested readers may also want to refer to the Healthy Housing Reference Manual (available at www.cdc.gov/nceh/publications/books/housing/housing.htm).
