According to 2011 American Community Survey data, Washington D.C. is the wealthiest metropolitan area in the country:

D.C. area residents have a median household income of $86,680, well above the national average of $50,502.

The large salaries may be attributable to the nearly 47 percent of workers who hold college degrees, making Washington one of the most highly educated areas in the country.

The list also shows more adults in the area were able to find employment during a down economic time. Just 5.8 percent of the workforce were unemployed in 2011.

Only 8.3 percent of Washington homes are living below the poverty line — the fifth lowest ranking in the country.

Here is some common traits of the wealthier cities in the United States:

The biggest factor in determining a city’s income, according to Alex Friedhoff, a Research Analyst at Brookings Institute’s Metropolitan Policy Program, is the underlying industries that employ the most residents, as well as the type of jobs. High-tech jobs, particularly those related to computers and information technology, tend to pay higher salaries and are more likely to be located in areas with affluent residents. On the other hand, most of the jobs in the lower-income metro areas tend to be in retail, service, agriculture and low-tech manufacturing.

A review of the employment characteristics of the different cities confirms this. Included among the richest cities are the information technology centers of Boston and Boulder, the finance hub of Bridgeport-Stamford, and the San Jose region, better known as Silicon Valley, home to some of the largest chipmakers and computer parts manufacturers in the world. Nationwide, 10.7% of workers are employed in professional, scientific, and management positions. Of the 10 wealthy metro regions, nine have a larger proportion of workers in that sector. In Boulder, 21.9% fall into that category.

In the poorest economies, there is a much higher proportion of low-end manufacturing and retail jobs. In the U.S. as a whole, 11.6% of workers are employed in retail. In the 10 poorest metro areas, eight exceed that number by a wide margin, including Hot Springs, Arkansas, where 17.3% of its workforce is employed in retail.

Based on these listed traits, perhaps we can make this conclusion: cities that have better adapted to the new information age economy based on innovation, computers, and highly educated workers are doing the best in terms of income. Places that haven’t been able to attract this kind of industry are playing from behind.

An important note about these stories: while headlines suggest this data is about cities, it is really about metropolitan regions. So when Washington D.C. is cited as the wealthiest city, this is not quite true; the region is the wealthiest. While some might that the city itself is necessary for the whole region to exist or thrive, a lot of this wealth plus many of the jobs are actually suburban. Don’t confuse the two though this often happens in the media.