You can access the spreadsheet here and download it yourself. However, for the duration of the current 116th Congress, we will be keeping this guide updated as membership in Congress changes whenever vacancies arise and when new data becomes available for the districts themselves, so be sure to bookmark the online version of the spreadsheet for the most up-to-date info. Furthermore, check out our original post on the guide for the start of the 116th Congress for charts and maps looking at the demographics of the members themselves.
We have also mapped out various demographic statistics for each congressional district using race, income, and educational attainment.
This first map demonstrates what the largest racial or ethnic group is among adult citizens, which we have chosen to analyze because it's a strong approximation of the largest grouping among eligible voters. Whites make up a majority in 78 percent of the districts, which is about 4 percent higher than their 74 percent share of voters in 2016.
While another six percent of districts have a white plurality, many of these actually are districts where black, Latino, or Asian American voters can consistently elect a member of their own demographic group in coalition with each other or because white voters are themselves politically divided. Nevertheless, it illustrates just how concentrated people of color are in relatively fewer districts than their national proportion, thanks in part to race-based gerrymandering.
This second map below shows the median household income within each congressional district. The national median income is $58,000, and the district with the highest income is California's 18th, which is based in Silicon Valley, at $122,000. Meanwhile, the lowest is New York's 15th, a Bronx-based district where the median household income is just $27,000.
Speaking of medians, there's one more informative stat we can analyze by ranking each district from highest to lowest median household income and looking at the income level in the district in the middle—the median district—which was Ohio's 8th in the suburbs and exurbs of Cincinnati. That district's median household income was $56,000, which means a majority of districts have at least a slightly lower income than looking at every household nationally.
(Note that because the court redrew Pennsylvania's congressional map in 2018, median income data will not be available until the 2014-2018 American Community Survey is released in early 2020, since it is not possible to calculate it with the Census Bureau's publicly available data on median income by other geographic units.)
The next map illustrates the percentage of adults aged 25 or older with a bachelor's degree or higher. Nationally, 31 percent of adults hold at least a bachelor's degree, and the district with the highest percentage is New York's 12th, which includes Manhattan's Upper East Side, at 72 percent. The district with the lowest percentage of degree-holders is California's 21st, a heavily agricultural district in the Central Valley, at just 8 percent.
Like with the income stats above, we can find the median district by ranking them all from highest to lowest share of college degree holders. Consequently, the median was a five-way tie among Kansas's 4th, Louisiana's 6th, North Dakota's At-Large District, Tennessee's 8th, and Washington's 5th, all of which were just shy of 29 percent. Thus, most districts have at least a somewhat lower proportion of college degree-holders than the national average.
In the Donald Trump era, there has been considerable public discourse over how white voters have polarized along educational attainment lines, with those who hold a college degree swinging Democratic and those without one trending Republican. This next map looks at the percentage of adults who have a bachelor's degree or higher among whites only. Nationally, 34.5 percent of white adults have a degree, and the district with the highest proportion is once again New York's 12th at 80 percent. The district with the lowest proportion is Kentucky's 5th, located in the heart of Appalachian coal country, at just 13 percent.
The median district is California's 31st at just below 33 percent. Like with all adults with a college degree, most districts have a proportion of degree-holders among whites that's slightly below the national average.
Of course, few political divides fall neatly along a binary, and even within the population of those who don't have a college degree, educational attainment levels vary dramatically. Indeed, a 60 percent majority of American adults at least have some college experience even though only about half that number attained a degree. Furthermore, 87 percent of American adults have at least a high school degree or GED, but many do not in certain districts. Indeed, this map below shows that in California's 40th located in eastern Los Angeles, just 54 percent of all adults have a high school degree or GED. By contrast, 96 percent of all adults in Colorado's Boulder-based 2nd District do.
The median district for high school degree-holders is a three-way tie among Missouri's 4th, Oregon's 2nd, and Pennsylvania's 9th, all of which have about 88.6 percent of adults holding at least a high school degree. Unlike the previous two education stats, the median district is actually slightly better than the national average. That is likely a byproduct of how high the national percentage is to begin with, since there are numerous districts like California's 40th with significant Latino immigrant populations that rank considerably below the national average of 87 percent, but it's impossible for any district to be as equivalently above average.
This final demographic map is a combination of the racial demographics for the adult citizen population discussed above and the proportion of white adults without a college degree. Since the vast majority of adult citizens are eligible to vote except for people who are disenfranchised due to felonies depending on state-by-state laws, this statistic approximates the proportion of eligible voters who are white and have no college degree, which is 45 percent nationally, a number that agrees with actual voter file statistics. The district with the highest share of these non-college whites is Kentucky's 5th at 84 percent, and the lowest is New York's 15th at just 2.5 percent.
Lastly, the median district is a four-way tie among Colorado's 5th, Indiana's 5th, Missouri's 2nd, and New York's 2nd, all of which are roughly 47 percent white without a college degree. Just as with the educational attainment stats alone, this stat indicates that a majority of districts have at least a slightly higher proportion of whites without a college degree than the national average.
You can find the 2016 presidential result by congressional district mapped at the top of this post (see here for a larger version). Running a statistical linear regression that compares the presidential margin in each district with the estimated share of eligible voters who are white without a college degree, we find that about two-thirds of the variance in the 2016 presidential results can be explained by that demographic marker alone (in stats-speak, that's an r-squared value of 0.68). As shown on the graph below, called a scatter plot, you can see this relationship at play.
Interestingly, that predictive power of the proportion of adults who are white without a college degree was quite a bit lower in 2018's House races where both parties were on the ballot—in other words, 394 out of the 435 districts—with it only explaining 54 percent of the variance in the House election results (r-squared of 0.54).
While some of the endless media attention on white voters without a college degree is deserved as these statistics show, there's still significant amount of what determines election voting patterns that simply can't be explained by isolating this particular demographic group at the expense of other factors. Indeed, the 2016 presidential result alone predicted 95 percent of the variance in 2018's House results (r-squared of 0.95), indicating that there are other factors driving partisanship that matter a great deal, too.
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