Jess Weaver Grey

By Jess Weaver • March 12, 2018

Complementing Harvard’s Map of the Month series, each week, Map Monday highlights a data visualization that enhances understanding of or helps resolve a critical civic issue.

8 Mile – in addition to serving as the title of the classic 2002 film starring a young Eminem – is known for its demarcation of Detroit’s racial and economic divide. The road separating the city’s “haves” and “have-nots” has become a symbol for income inequality visualized. How real, though, is the starkness of the economic disparity of the neighborhoods straddled by 8 Mile?


According to “Mapping Incomes,” a new story map produced by Esri, 8 Mile Road does indeed cover a real economic chasm in Detroit – and that gap is only growing. In Los Angeles, Philadelphia, Chicago, and Detroit, Esri’s maps illustrate the widening socioeconomic disparities in each city’s geography, revealing trends in wealth and poverty concentration, as well as income diversity, a key indicator for social mobility and neighborhood vitality.


Leading with the city of Chicago, the map first illustrates census tracts by predominant household income bracket, unveiling the geographic spread of wealth throughout the city. The brightness of the color indicating each distinct income bracket represents its relative predominance to households of other incomes. Unsurprisingly, downtown and particularly waterfront Chicago gleans the brightest blue, marking the city’s highest predominance of households earning more than $100,000. Close by, swaths of orange shine brightly, representing areas adjacent to downtown dominated by households earning under $25,000, showing the stark socioeconomic disparity between these highly proximate neighborhoods.

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More middle income and economically diverse neighborhoods can be seen north, south, and west of downtown, most likely an illustration of the gentrification trends experienced by cities across the United States. In fact, the user can compare the economic disparity in comparison to the national average of households in the highest and lowest income brackets, creating a comparative portrait of Chicago’s wealth and poverty concentration.


In addition to examining areas of highest economic disparity, the map shows areas of high economic diversity. Counter-intuitively, downtown Chicago – undoubtedly the city’s wealthiest area – also appears to be its most diverse in terms of household income. The northern-most point of the city, home to luxury condos, is less diverse in contrast to neighborhoods slightly to the south, where the split between the other income brackets – middle class and lower income populations (perhaps residing in affordable housing units) – generates a much more mixed income distribution. The trend of highly affluent neighborhoods just north of much more economically depressed communities is not limited to Chicago; similar trends can be seen in cities like Seattle and Boston. Unlike Seattle and Boston, however, Chicago is not included in the nation’s 100 most economically diverse cities, pulling at 108 in contrast to the west coast city’s 8th and east coast city’s 50th places, respectively.


It’s worth noting that income diversity is not necessarily a sign of economic inequality. Take Los Angeles, the second city examined in Esri’s story map. There, even the wealthiest neighborhoods boast high levels of income diversity, indicating greater economic opportunity for the area’s less affluent residents. Unsurprisingly, the city’s least economically diverse neighborhoods are also its poorest, indicating a wide gap in social mobility and neighborhood vitality.

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New York’s boroughs, by contrast, illustrate far more significant disparities and lower levels of income diversity, most dominated by a single income bracket. Wealthy neighborhoods like Manhattan and western Brooklyn are juxtaposed with lower income communities in the Bronx and other areas of Brooklyn, where the creep of gentrification is especially visible.


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Gentrification, in which economic opportunity typically precedes displacement, is also present in Detroit, which is by popular account America’s next up and comer. Those trends, however, are highly limited to specific areas (particularly the suburbs), while over 250,000 residents live below the poverty line. A similar divide is evident in Philadelphia and Houston, where more predominantly affluent areas located outside the urban core, though university districts have generated more economically diverse pockets close to downtown.


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Compared to rural areas, particularly in the South, the concentration of America’s wealth is in its cities. Many of those cities, as evident in Philadelphia, Houston, and Detroit especially, reflect that divide even within their own borders, with the urban center concentrating high levels of both wealth and poverty.


Rap battles aside, the portrait of Detroit’s 8-Mile might be over-dramatic…but it’s not far off. This map reveals an important truth for planners and the public sector: economic homogeneity limits economic opportunity, and is most likely to be found in America’s poorest communities. By understanding the relationship between income diversity and economic vitality, incentives for development or more targeted delivery of services might be more effectively implemented.


Capitalizing on the recent tax bill’s provision of national opportunity zones, intended to incentivize investment and development in lower-income neighborhoods, for instance, offers cities a clear opportunity for more targeted initiatives aimed economic opportunity. Being able to identify likely sites of gentrification, furthermore, might allow planners to be more proactive in diversifying affordable housing options, especially mixed-use units and multi-family zoning policies. Before economic inequality can be addressed city-wide, it must be fully understood – neighborhood by neighborhood, even mile by mile.