Increasingly, the rich live among the rich, and the poor among the poor. Especially in the big cities of Texas. Less so in Miami, Cincinnati, Boston, Sacramento, and Portland.
A recent blog here focused on a report by the Pew Research Center called “The Rise of Residential Segregation by Income.” This report concluded that our neighborhoods have become significantly less economically diverse in the 30 years from 1980 to 2010. We have moved in a major way from more economically diverse neighborhoods to more homogenous ones. This has happened on both ends of the economic divide. The portion of lower-income households who live in neighborhoods where the majority of households are lower income went from 23% to 28%. And the portion of higher income households who live in neighborhoods where the majority of households are higher income has increased even more so from 9% to 18%.
This report also showed that there is a wide range in residential income segregation among different U.S cities.
The report compared the 30 largest U.S. metropolitan areas. Looking at census tracts (each with about 4,200 people), each city was assigned two numbers:
1. the percentage of lower-income households living in census tracts which contain a majority of lower-income households, and
2. the percentage of higher-income households who live in census tracts which contain a majority of higher-income households.
Adding these two numbers together results in the Residential Income Segregation Index score.
Here is a table showing certain U.S. cities, and their respective lower-income and higher-income residential income concentrations, and their Residential Income Segregation Index (RISI) scores:
| CITY | LOWER-INCOME | HIGHER-INCOME | RISI SCORE |
| San Antonio | 38 | 25 | 63 |
| Houston | 37 | 24 | 61 |
| Dallas | 37 | 23 | 60 |
| Philadelphia | 38 | 13 | 51 |
| Miami | 32 | 17 | 49 |
| Cincinnati | 33 | 14 | 47 |
| Riverside, CA | 21 | 9 | 38 |
| Boston | 28 | 8 | 36 |
| Sacramento | 28 | 7 | 35 |
| Portland, OR | 25 | 5 | 25 |
Notice that the range in the concentrations among lower-income households is from 25% to 38%, a comparatively narrow range. So lower-income people live among other lower-income people similarly around the country’s cities.
In contrast the range in the concentrations among higher-income households from 5% to 25% is much wider. So on the two extremes, in San Antonio a higher-income household would be 5 times as likely to be living in a majority higher-income neighborhood than in Portland.
Why is this? The report wasn’t designed to investigate this, but the authors still speculate:
It is beyond the scope of this report to analyze in any detail the causes of these metro area differences. Among the factors that may play a role are historical settlement patterns; local housing policies, zoning laws, real estate practices and migration trends; and the characteristics of the local economy and workforce.
Two broad patterns seem worthy of note. First, in looking at the changes over time in the nation’s top 30 metropolitan areas, one finds that most of the metros whose RISI scores have had the largest increases have also experienced significant population growth fueled by in-migration.
For example, Houston, Dallas, San Antonio, Phoenix and Miami have all been among the nation’s fastest-growing large metropolitan areas during the past three decades—a growth that has been fueled in part by an influx of low-skill, low-wage immigrants from south of the border and in part by an influx of high-skill, high-wage workers and well-to-do retirees. These dual migration streams could well have contributed to a rise in residential segregation by income.