(September 2012) The number of households in the United States more than tripled between 1940 and 2010—from 35 million to 117 million—and household growth outpaced population growth in every decade across this time period. Accompanying this growth in the number of households has been a gradual but significant transformation of household structure. While in 1940 the overwhelming majority of households (90 percent) contained families—two or more persons who were related to each other—by 2010, this share had dropped to 66 percent.
Household structure plays an important role in the economic and social well-being of families and individuals. The number and characteristics of household members affect the types of relationships and the pool of economic resources available within the household. Although families may provide social and economic support to members who reside in different households, an individual's overall well-being is heavily influenced by his or her living arrangements. Household structure may also have a broader impact by increasing the demand for economic and social support services. For example, the growth in single-parent families has increased the demand on the welfare system, while the rising number of older persons living alone may soon strain the supply of home health care and other personal assistance services.
A household comprises all the people who occupy a single housing unit, regardless of their relationship to one another. A household may be a family, for example, or it may be a group of roommates or two unmarried partners. In this Population Bulletin, we examine the dramatic changes in U.S. household structure in the last 70 years, and how households differ by important characteristics such as age, race and ethnicity, and education. We analyze trends in the key social processes driving household change, including marriage, divorce, and marital and nonmarital childbearing. We also examine groups of people born in the same year or decade (birth cohorts) to see how the lifetime experiences of individuals have changed. New types of households and families are emerging in the United States in response to changing social norms, economic conditions, and laws governing marriage, and we discuss challenges in capturing these new family forms in demographic surveys.
Changing Household Structure
Prior to World War II, more than 75 percent of households in the United States included married-couple families (see table). In 1940, married couples with children represented 43 percent of all households; married couples without children represented 33 percent of households; single-parent families accounted for only 4 percent of households; and other types of family households accounted for 9 percent. Nonfamily households made up only 10 percent of households nationwide, and most of those were persons living alone.
Percent Distribution of U.S. Households by Type, 1940-2010
| Married couples with children
| Married couples without children
| Single parents with children
| Other family
| One person
| Other nonfamily
Note: Percentages for subcategories may not sum to category totals due to rounding.
Source: U.S. Census Bureau, decennial censuses from 1940 to 2010.
In 1960, as the post-war baby boom neared its end, married-couple families with children increased slightly to 44 percent of all households, while the share of married-couple families without children declined to 31 percent, and one-person households jumped from 8 percent to 13 percent.
By 1980—just 20 years later—a significant change in household structure had taken place. The share of family households had dropped to 74 percent, and the share of nonfamily households had risen to 26 percent. Married couples with children had declined to 31 percent—virtually the same share as married couples without children—and one-person households had increased by 10 percentage points to almost one-fourth of all households.
Since 1980, the pace of change has slowed but the transformation in household structure has continued, particularly the decrease in married couples with children and the increases in both cohabiting couples and one-person households. During the next 20 years, the decline in married-couple families with children will accelerate as more baby boomers reach retirement age, creating a new generation of empty nesters.
Linda A. Jacobsen is vice president, Domestic Programs, at the Population Reference Bureau. Mark Mather is associate vice president, Domestic Programs, at PRB. Genevieve Dupuis is a research associate, Domestic Programs, at PRB.