Katherine Newman is the dean of the Krieger School of Arts and Sciences at Johns Hopkins University and author of the forthcoming book, "The Accordion Family: Boomerang Kids, Anxious Parents and the Private Toll of Global Competition."

Having studied multigenerational families in six different countries, I can safely say that there is no uniform answer to the question of whether extended families under one roof is good or bad for the economy. The same demographic pattern that is defined as a national catastrophe by the Japanese elicits something closer to a shrug in Italy. Spanish families are furious with the government over deregulated labor markets and high housing prices that push them into “accordion families.” One rarely hears about the responsibilities of government for creating boomerang kids in the United States.

In the Nordic countries, where the state provides many benefits for young adults, the multigenerational family is almost unknown.

In the Nordic countries, where the state provides benefits for young adults in the form of free higher education, generous housing allowances and unemployment insurance even for those who have never worked, the multigenerational family is almost unknown. The social democracies have intervened to support independence from the natal home in ways that are unimaginable in the U.S. or Japan.

The economic consequences of these demographic trends are quite serious. When young people stay with their parents for a long period, family formation is delayed, fertility falls, populations age and productivity declines. Boomers may find it harder to retire if their savings are absorbed in the support of their adult kids.



The emotional consequences are more variable. Many parents enjoy the presence of their adult children. They do not suffer much of a generation gap because they share tastes in popular culture and have more relaxed views of sexual relations, which means their children can continue a semblance of a private life under their roof. But this tends to last only as long as signs of progress toward independence are visible. If Johnny is playing video games in the basement, the situation can become fraught in a hurry.