Census Estimates for 2006 -> 2010 Apportionment

[muon2]

The Census Bureau released its new estimates for the population of the states as of July 1, 2006. As in past years I have used that data to project the April 1, 2010 apportionment populations. This requires finding the population growth in the resident population for each state, then applying that to the apportionment population.

One unusual event in the year between estimates was hurricane Katrina. LA saw a drop of 220 K in the 12 months following the hurricane. If I used the normal methodology, that would project a continued decline through 2010. Instead, for LA I took the percentage growth through July 1, 2005, then applied that to the new estimate for July 1, 2006. This gives some projected growth over the next 3 3/4 years.

Based on this projection, the following adjustments would be required to reapportion the seats in 2010:

AZ +2
CA +1
FL +2
GA +1
IL -1
IA -1
LA -1
MA -1
MI -1
MN -1
MO -1
NV +1
NY -2
OH -2
PA -1
TX +4
UT +1

Compared to last year's projection this is a shift of one seat from FL to TX. The last states awarded seats were AL 7 (431), PA 18 (432), NJ 13 (433), CA 54 (434) and TX 36 (435). The fourth new TX seat is clearly on the bubble and benefitted from the Katrina migration.

The next five seats would go to MN 8 (436), FL 28 (437), NY 28 (438), WA 10 (439), and OR 6 (440). Seat 436 is important if Congress passes the DC representation act since that seat could be real in 2010. The appearance of WA and OR on the bubble list is new this year, and perhaps suggests that the Census Bureau is seeing a new growth spurt in those states. If it's sustained those two states may move up in the next three years.

[muon2]

Well obviously, everyone is using different proportion formulas.

This guy says that Washington and Oregon would gain a seat each!! FINALLY A BLUE STATE GAINING A SEAT!! YAY!

http://www.polidata.org/census/st006nca.pdf

It's important to distinguish between the method used by polidata and my analysis. Polidata only looks at the estimates from the last two years, averages the percentage increases, and applies the average times four years to the estimate base. This method overweights any accidental fluctuations in the Census estimate, and overly favors any recent upward bump in the data.

In my analysis, I take the estimate data back to the base of April 1, 2000 and determine an annual increase with correct compounding of the percentages and the three month offset between the Census day and the estimate date of July 1. This avoids adding an extra three months of growth in 2010. Also, I apply that increase not to the estimate base from 2000, but instead to the apportionment base. This is the value that includes overseas population and is only used for apportionment purposes, not redistricting or estimates. This will pick up differences between states that have different fractions of their population overseas.

It may be that the uptick in growth rates in the Pac NW are real. If so, I'll catch that as subsequent years' estimates come from the census. I did move WA and OR to the bubble with seat priority 439 and 440. I don't think the statistics warrant moving them down to 435 or less.

[muon2]

Thanks.

Is it assured that Texas gains a 4th seat? I kinda doubt it somehow. And I do believe that Florida's expolsive growth rate wont last forever, lol.  Florida has a lot of geography problems. I do believe Texas will one day be the nation's largest state, I gaurentee that!

I am glad Arizona is gaining two seats! I hope we can make it a DEM Stronghold! Well maybe not a dem stronghold, but to make it more Democratic. I hope these census numbers show the democrats that WE HAVE TO make inroads in the upper south and mountainwest.

California gain of an electoral vote suprises me.

James

I would agree that the TX seat is not at all a sure thing. There was a big bump due to Katrina emigrants, and that is not likely to repeat before the end of the decade. However, the Census release for 2006 also included an upward estimate for TX on 7/1/05 of about 68 K, and that predates Katrina.

AZ has been pretty steady to pick up two seats with every estimate released this decade. It's possible that they would only get one, but that should be a surprise if it happens.

CA is on the bubble with the projection of a 54th seat. It shouldn't surprise any demographers if they get it or not. It will surprise the media if they don't get one as they have become used to seeing CA get seats with every reapportionment.

[muon2]

I'm not familiar with how Census estimates work, and I know this is kind of a vague question, but can you expand on the uptick in the Pacific Northwest?  Last time I checked, I think that Oregon was considered a longshot in gaining a seat, while Washington wasn't even much in the consideration.  What happened, and any idea why the Census is seeing a bigger-than-expected gain?

The Census gives a faily detailed explanation of their methodology. The change in annual percentage growth in WA and OR over the decade only went from 1.2% to 1.3% as I compare last year's estimates to this year's. With compounding that was enough to put both states on the radar.

Both WA and OR had above average CD populations after the 2001 redistricting. Both are also growing at slightly above the national average. Those factors point to an eventual seat each, but most forecasters would have placed their gains in 2020, not 2010.

You asked why the change. The real answer to your question lies in the estimates of county population since they are used to build the state estimates. That data won't be released until Mar, so we'll have to wait until then.

[muon2]

In response to some of the questions that frequently arise, I've put together a web page with a description of my methods and the projections for each state.