Less Diverse = Older

[imgbelt img=diversity.gif]Between 2000 and 2010, most of the U.S. became more ethnically diverse.
But metro counties diversified faster ethnically than did rural
counties. Relatedly, the median age in rural counties grew faster than
the national average.


See this earlier story about aging in rural counties.)

Why is this the case? 

And can this trend be reversed?

Immigration is known to play a key role in not only helping the population grow but also providing young workers. It is estimated that by 2050, nearly one in five Americans will be an immigrant. 

A study by the Pew Research Center found that Hispanics accounted for 54% of labor force growth during the 2000-2010 decade and are expected to account for 74% of growth in the 2010-2020 decade. 

So, is there a relationship between immigration (measured by ethnic diversity) and age (measured by the median age) at the county level in the U.S.? Do these relationships change between metropolitan, small city, and rural counties?

The answer to both questions is yes. Counties that are growing older are less diverse than counties with lower median ages. And rural counties are growing older than counties in metro areas.

In order to address these questions, we looked at three variables: median age; old-age dependency ratio; and an ethnic diversity measure.  We looked at these variables at two points in time: 2000 and 2010. 

Measuring Old-Age Dependency

The old-age dependency ratio is used extensively by social scientists to better understand demographic trends. This ratio calculates the number of residents over 64 years of age for every 100 residents of working age (between 16 and 64). Ratios ranged from a low of 4.1 — that is, 4.1 people over 64 to every 100 of working age  — to a high of 89.2 in 2010 among U.S. counties. 

As with ethnic diversity, all geographic areas witnessed an upswing in their old-age dependency ratio over the 2000 to 2010 time period.  (See the chart below.)