2 January 2020 — 1553 mst
Projections of Montana’s population to 1 April 2020 vary
On New Year’s Eve, the U.S. Census Bureau released its population estimates for 1 July 2019. Montana’s population has increased to the point where it may be allocated a second seat when the U.S. House of Representatives is reapportioned next year.
The key word is “may.” The new estimates come with a lot of caveats, most of which have not been addressed in depth by news reports on the possibility of gaining a second seat.
The estimate is an estimate, not a hard and fast number based on a definitive count.
… Overall, our estimates time series from 2000 to 2010 was very accurate, even accounting for ten years of population change. The average absolute difference between the final total resident population estimates and 2010 Census counts was only about 3.1 percent across all counties.
We produce estimates using a cohort-component method, which is derived from the demographic balancing equation:
Population base + births - deaths + migration = population estimate
- Migration is the sum of migration into the state and migration out of the state and can be a negative number. Flathead Memo note.
All estimates have a margin of error, a plus/minus factor. Thus far, I have not found a table with the Census Bureau’s MOE for its new estimates, but the MOE exists.
A second caveat is that the estimates of reapportionment are based on projections of the Census Bureau’s estimates for 1 July 2019. Election Data Services, for example, used a variety of methods and population bases to project the census estimate to 1 April 2020. All projections have a margin of error.
The table below displays four projections by EDS, and three by Flathead Memo. My numbers are the result of a quick and dirty, ruler and graph paper, analysis that treats the population of a function of time. At best, this is an approximation that assumes the future will be the past written larger.
Montanans should be mindful of the uncertainties inherent in the estimates, and of the magnitude of those uncertainties. Montana is right on the bubble for gaining a second House seat. An estimate that’s on the high side may falsely predict the gain of a seat.