Here is a comprehensive feature article from CQ Politics about the reapportionment that will result from the 2010 Census (click HERE for full article):
The once-a-decade process for redrawing the map of the House of Representatives has two distinct parts with similar-sounding, multisyllabic names. Redistricting, the drawing of the lines within each state, is the second part. Reapportionment, deciding how many House seats each state will have, comes first.
There’s likely to be much more suspense about Part 2 than about Part 1. Although the governors, state legislators and probably some judges will be fighting over congressional district boundaries for much of 2011 and 2012, how many seats get assigned to each state will be decided formally, relatively straightforwardly, by the end of next year, based on the results of the 2010 census.
But the outcome, in broad terms, is not in doubt. As in every reapportionment since World War II, more seats will be awarded to the Southern and Western states, and taken away almost exclusively from the states of the Midwest and Northeast.
The power shift will not be as great as it was over the latter half of the 20th century, when the population surges in the Sun Belt eclipsed the modest growth in the Rust Belt because of a variety of factors: technological advances — air conditioning, first and foremost — that boosted the appeal of life in the warm-weather states; changes in the American economy, especially the decline in manufacturing in the nation’s northern half; the rapid increase in the Hispanic population; and the growth of the retirement and tourism industries that favored the temperate climes and expanses of the South and West.
Based on the most recent detailed population projections from the Census Bureau, the nonpartisan Election Data Services Inc. (EDS) — a consulting firm in Manassas, Va., specializing in political demographics — projects that a dozen seats will be reassigned next year, with eight states gaining some strength in the House and 11 states losing some.
Twelve seats were shifted after the 2000 census; the reapportionment upheaval was significantly greater after the 1990 census (19 seats moved) and the 1980 census (17 seats). The seat-shift projection may change at the end of the year, when the Census Bureau will release new populations of the 50 states based on estimates made this summer.
Not only will the reapportionment signal the start of redistricting, it will also inform the early strategizing about the 2012 presidential election, because each state’s strength in the Electoral College is equal to the size of its total congressional delegation: House members plus senators.
For an event of rather momentous political consequences, reapportionment hardly captures the imagination of the average American. It begins with a national population head count that few people give more than a few minutes’ notice every 10 years. And it concludes with the application of a formula for apportioning seats that only someone with a doctorate in statistics can love, or truly comprehend.
Using forms mailed to every household in March, and follow-up interviews with people who don’t return those forms, the Census Bureau will seek to determine the precise populations of each state on April 1. The secretary of Commerce, who oversees the agency, has until Dec. 31 to announce those population counts. (In 2000, the job got done three days before the deadline.)
The totals provide the raw data for reapportionment based on the “method of equal proportions,” which Congress has used since 1941 to divvy up House seats among the states. The formula is actually used to parcel out only the 385 seats that remain after each of the 50 states is assigned the one seat it is guaranteed under the Constitution.
The rest of the seats are handed out based on statistical “priority values” assigned to each additional seat that a state might get. In as close to plain English as the formula will allow, these priority values are calculated in a two-step process that requires dividing a state’s population by the square root of the product of the number of seats it’s already been assigned and that number plus one. The priority numbers are then rank ordered: “State A” will get an additional seat if its priority value for that seat is greater than any other state’s. The seats are disbursed to states based on these rankings until all 435 have been awarded.
The reason at least a handful of seats get transferred each decade is that reapportionment is a zero-sum game: The size of the House was fixed at 435 seats in a law enacted 80 years ago. The fact that the number of House seats has stayed the same even as the population has soared means a vast increase in the number of constituents represented by most House members. The average district population in the coming decade will be about 710,000 people, 10 percent more than in this decade and 24 percent more than in the 1990s.