To illuminate the differences between the seats each party holds, CNN producer Aaron Kessler used census data to track some of the key characteristics of all 435 House districts. That exercise, employing data from the American Community Survey's 2012-2016 district-level estimates, produced a stark divergence between the 235 House Democrats and the 199 House Republicans (for the purpose of this analysis, CNN treated the North Carolina House seat enmeshed in allegations of voter fraud as vacant).
The divergence is apparent across every key measure.
In the new House, just over three-fifths of the Democrats represent districts where the minority share of the population exceeds the national average of 38%. Almost exactly 85% of House Republicans represent districts that are more white than the national average of 62%.
Almost three-fifths of the Democrats represent districts where the share of adults holding at least four-year college degrees exceeds the national average of 30.3%. Over three-fourths of the House Republicans represent districts with fewer college graduates than average.
Nearly three-fifths of House Democrats hold seats where the median income exceeds the national level of $55,322. Two-thirds of House Republicans hold districts where the median income lags below the national level.
Nearly 54% of the House Democrats hold seats where the median age is younger than the national level of 37.7. Almost exactly 60% of House Republicans hold districts that are older than the national median.
Just over three-fifths of Democrats represent districts where the immigrant share of the population (the portion of people born abroad) exceeds the national average of 13.2%. Over 90% of House Republicans represent districts with fewer immigrants than the national average. (These numbers do not include the 18 seats in Pennsylvania, where the immigrant population was not available for the state's recently redrawn districts.)