The Census Bureau released its final intercensal estimates of United States population on Monday.  These are figures released every year to track the flow of population in the United States, and to give an idea of what to expect in the decennial count.

They are important because the 2020 census will determine the next congressional reapportionment.  By looking at the estimates, we can get a sense of how things are likely to turn out the following year.

To estimate the actual census outcome, some back-of-the-envelope calculation is in order.  I took the (estimated) changes in population in every state from 2017 to 2018, and then again from 2018 to 2019.  I created a weighted average by counting the 2018-2019 changes twice and the 2017-2018 changes once.  I then assumed that this would be the amount by which state populations would grow (or shrink) come the official count in 2020.

Using the current apportionment formula (known as the Method of Equal Proportions), we can estimate the following changes:

  • Texas should gain three seats
  • Florida should gain two
  • North Carolina, Colorado, Arizona, Montana and Oregon should gain one each
  • Alabama, California, Minnesota, Illinois, Michigan, Ohio, West Virginia, Pennsylvania, New York, and Rhode Island should each lose a seat.

Of course, it is difficult to know exactly how this would play out in redistricting. Obviously, the West Virginia and Rhode Island seats would have to be taken out of the Republican and Democratic columns, respectively (barring a major surprise next year).  It is difficult to eliminate an additional Democratic seat from Ohio (though not impossible), while drawing an additional Democratic seat in Oregon is unlikely (though not impossible).

In the Electoral College, President Trump would gain electoral votes, but these changes would not take effect until the 2024 election (Trump could theoretically run if he loses in 2020).

These are, however, just estimates, and we have been surprised in the past.  The most vulnerable seats are (in increasing order of vulnerability): Illinois’ 17th District, Florida’s 29th, Texas’ 39th, Montana’s 2nd, and New York’s 26th.  The next seats subtracted, should the actual count for some of the previous seats fall short of estimates, are (in order): Alabama’s 7th, Minnesota’s 8th, Ohio’s 16th, California’s 53rd, and Rhode Island’s 2nd.