The recession may have some unintended benefits for cities that have been losing population.

A new study from the Brookings Institution has found that fewer Americans relocated to new cities in 2007-08 than in any year since World War II. The study, “The Great American Migration Slowdown: Regional and Metropolitan Dimensions” reported that northern cities that had been losing residents began to retain them instead, in contrast to the long-term trend. The study, which uses data from three different Census programs as well as the IRS migration flow data, also found that urban cores had unexpected “windfall” gains of residents, and out-migration declined from many major metropolitan areas. As you might expect, the highest mobility is among people aged 20-29 years old, but that migration rate fell sharply in 2008-2009. Job opportunities that might have beckoned college graduates just a few years ago disappeared, so they stayed in the same place.

While migration may begin to rise back to historical norms with the national economic recovery, cities have a brief window in which they may be able to entice young, college-educated residents to put down roots.

The study looks at migration from several aspects. Migration was highest among those with at least a college degree — but migration among that cohort fell as well. When viewing by housing tenure, there was a sharp decline among renters.

The report examines net migration by state and city as well, with a dimension of whether the migration is domestic or international. This yields some interesting findings. For example, for the years 2000-2008:

Washington, D.C. had net positive migration. It gained 245,000 international residents but lost 121,000 domestic residents.

Chicago had net negative migration. It gained 386,000 international residents but lost 507,000 domestic residents.

The state of Michigan had net negative migration. It lost 470,000 domestic residents, but it gained 152,000 international residents. Ohio had a similar pattern.

These migration patterns may offer lessons for planners and leaders in shrinking cities. If a city is attractive to international immigrants, perhaps part of the city’s master plan and economic development strategy should seek to attract them in larger numbers. Outreach efforts to other countries (particularly if there are a few ethnicities with concentrations in a given city) may be useful. Business licensing and practices may need to be adapted to encourage small-scale entrepreneurship. The city may want to use its cultural diversity in marketing as well.