ANN ARBOR—The United States is going through a major demographic transition, according to a University of Michigan analysis showing a geographic divide that reflects a shift toward new patterns of household formation.

The analysis, presented March 30 at the annual meeting of the Population Association of America, shows that this divide is linked to county-level voting patterns.

According to sociologists Ron Lesthaeghe and Lisa Neidert at the U-M Institute for Social Research (ISR), 30 or 40 years ago western European nations moved away from classic family formation patterns of early and universal marriage, fertility within marriage and the use of contraception to stop having children. Instead, these nations increasingly follow patterns that Lesthaeghe has termed the “Second Demographic Transition”?later ages at marriage, adults living alone or cohabiting, slower rates of remarriage, fertility outside of marriage and the use of contraception to delay or forego childbearing.

The researchers show that despite a belief that the U.S. is an exception among developed, democratic nations, with a population that is more religious and socially conservative than that of most European nations, these same kinds of transitions are in fact occurring in the United States among the white non-Hispanic population.

“The spatial variation of these demographic patterns in the U.S. is very important,” said Lesthaeghe, who, along with Neidert, is currently tracing household formation patterns in the U.S. over time as well as space. “The geography of the second demographic transition unfolds along politico-religious lines.”

A map of this transition shows the spatial distribution of the factors characteristic of the Second Demographic Transition in all 3,131 U.S. counties. The areas with high concentrations of newer, less traditional family patterns tend to be at the edges of the country, on the west and east coasts, while the areas with more traditional family patterns include Utah, southern Idaho, and the south central states.

In another map, Neidert and Lesthaeghe use the same color scheme to show the percentage of the population who voted for George W. Bush in the presidential election of 2004 by county. The results are very similar to that shown in a map of the demographic transition factors.

The researchers have also analyzed these spatial patterns using population cartograms, which scale the area of each county in proportion to its population. One cartogram shows the Second Demographic while another cartogram shows the vote for Bush in the 2004 presidential election.

In the cartograms, the traditional, red areas of the country are much less prominent than they are in the geographic maps?a fact that has often been overlooked in discussions of the political divide in the United States.

Established in 1948, the University of Michigan Institute for Social Research (ISR) is among the world’s oldest academic survey research organizations, and a world leader in the development and application of social science methodology. ISR conducts some of the most widely-cited studies in the nation, including the Reuters/University of Michigan Surveys of Consumers, the National Election Studies, the Monitoring the Future Study, the Panel Study of Income Dynamics, the Health and Retirement Study, and the National Survey of Black Americans. ISR researchers also collaborate with social scientists in more than 60 nations on the World Values Surveys and other projects, and the institute has established formal ties with universities in Poland, China and South Africa. ISR is also home to the Inter-University Consortium for Political and Social Research (ICPSR), the world’s largest computerized social science data archive. Visit the ISR web site at www.isr.umich.edu for more information.

Copy of the presentation and more informationMaps related to the research