When younger Americans move, it tends to be to places that are more racially and ethnically diverse than where they leave. But for older Americans, the opposite is often true.

A new study published in the journal Demography offers a first look at how local-level migration influences integration and segregation. It explores the "white flight" of families fleeing urban areas for whiter neighborhoods, suburbanization and other migration patterns for U.S. counties from 1990 to 2000 and from 2000 to 2010.

Most notably, researchers found stark differences across age groups, with migration of people under 40 increasing diversity -- both in their new homes and the jurisdictions they left -- and migration of the 60-plus group effectively reducing it.

In particular, whites over age 60 were shown to move most often from more diverse to less diverse counties over the time periods reviewed. This trend, says Kenneth Johnson, co-author of the study and a University of New Hampshire demographer, is mostly a result of either white flight or retirees who move to warmer climates and retirement destinations that don't tend to be very diverse.

By contrast, older African-Americans and Hispanics -- who didn't move as frequently -- increased diversity by typically migrating to whiter places.

Meanwhile, migration by adults between the ages of 40 and 60 had only marginal net effects on diversity as a whole. Middle-aged adults increasing segregation by moving largely canceled out those who decreased it.

Johnson says the migration patterns were the same for both decades, although overall migration did slowdown as a result of the recession.

When all age groups are considered, migration helped reduce segregation throughout most of the country, increasing diversity in about two-thirds of all counties between 2000 and 2010. Effects were minimal in 32 percent of counties, while migration “significantly diminished” diversity in just 2 percent of counties, according to the analysis.

Net migration’s effects on diversity varied somewhat, depending on how rural or urban counties were. The study found its effects were strongest for suburban counties on the fringe of urban regions, particularly in the Northeast and in the metro areas of Atlanta, Chicago and the Twin Cities.

Migration's influence on diversity was weakest for rural counties adjacent to metropolitan areas. Much of Texas and parts of the Southwest, for instance, experienced relatively little integration and even saw segregation increase in some cases.

Source: Winkler and Johnson, Demography, 2016; Caresy School of Public Policy issue brief


The often-cited local migration data published by the U.S. Census Bureau do not describe demographic characteristics. So the study's researchers first added up county birth and death records (which include age, race and ethnicity information) from the National Center for Health Statistics. Expected population totals from decennial censuses were then compared with actual counts at the end of the decade to delineate migration totals for specific demographic groups.

The study’s unit of geography was limited to counties, however, and it's worth noting that diversity often varies greatly across neighborhoods within counties.

Along with migration, natural changes further shape a county’s demographics. Racial and ethnic minorities now make up the majority of babies born in the U.S., while older whites account for the majority of deaths. The report notes that in areas where migration promotes greater integration, natural changes often have the opposite effect. This is particularly true for adults between the ages of 20 and 39: Their net migration decreased segregation, while natural changes exacerbated it.

It’s much harder to pin down exactly what role racial discrimination plays in any migration patterns. Previous studies relying on surveys conclude that white Americans, particularly those with young children, prefer not to live in predominantly black neighborhoods. Some, however, move to mostly white suburbs strictly for bigger houses. Many retirement destinations -- including rural areas near lakes or mountains and Sun Belt communities -- also tend to be more white.

“If [whites] are moving to a recreation and retirement destination, it may be because of the physical attributes of those areas,” says Johnson. “It might not necessarily be that they don’t want to live in a diverse community.”

More recent Census data not considered in the study has shown that migration has picked up after stalling during the economic downturn. The Census Bureau’s latest county population estimates for 2015 indicate an acceleration in moves from urban to suburban areas.

“The volume of migration and the patterns are reverting to more typical patterns of the pre-recession period,” says Johnson.

Those who recently left urban cores for suburbia are likely living in whiter communities than before. But many growing suburban and exurban areas have become much more diverse, too.

The Baltimore region exemplifies one area where this type of transformation is slowly taking place. The concentration of racial and ethnic minorities within the city has remained stable in recent years. But suburban Baltimore County, which surrounds the city, has experienced a significant influx of non-white individuals and families.


One important related question that hasn’t been answered is whether millennials will follow migration patterns of prior generations as they age.

Many theorize that millennials are fundamentally different than prior generations in that they desire urban amenities and seek to live out their lives in cities. But in some areas, steep housing prices and minimal availability of family-sized units have already pushed millennials out to the suburbs. So far, demographers and local officials have offered varying reports of what’s happening on the ground, suggesting it will likely play out differently across cities.

Regardless of where millennials end up, though, they’ll be living in neighborhoods much more diverse than those of their parents.