By 2020, for example, New York stands to lose five House seats while California, already the largest state delegation with 52 members, would add nine for a total of 61, researchers at the Population Reference Bureau report.
Overall, 25 of the House's 435 seats could shift between now and 2020, with the South and West gaining at the expense of the Northeast and Midwest, the group says, adding the predictions are based on current growth statistics. Researchers admit many factors could change the outcome.
|Among The Findings|
California, already No. 1 with a population of 32.6 million, could grow by 17 million over the next two decades. The state could gain one seat after this year's census and nine seats by 2020, increasing the delegation from the current 52 to 61.
New York's delegation stands to drop from 31 now to 26 in 2020, even though statisticians estimate the state's population will have grown from 7.6 percent between 1990 and 2020, from 17.9 million to 19.3 million. By comparison, California's predicted growth rate is 52 percent.
Also projected to lose seats by 2020 are Pennsylvania (four), Michigan and Ohio (three each) and Illinois (two). Their current size: Pennsylvania with 21 House members, Illinois with 20, Ohio with 19 and Michigan with 16.
Forecast to add House members are Texas (five), Florida (three) and Georgia and Arizona (two each). Their current size: Texas with 30 House members, Florida with 23, Georgia with 11 and Arizona with six.
Montana, which has one at-large representative now, would gain a second seat after this year's census and would keep the seat through 2020.
"It is a continuation of recent population trends," said Mark Mather, an analyst at the nonprofit, Washington-based organization.
The group forecast the size of states' House delegations based on population projections for 2020.
"We have to be careful we don't exaggerate the influence and the corresponding lack of clout because a state loses numbers in a congressional head count," said G. Terry Madonna, political science professor at Millersville University in Millersville, Pa.
"While more is better, I'm not convinced you'll have a small or medium-sized state that doesn't have significance in national legislation."
"We wanted to look far enough in the future so that you have some exciting change to look into, but not too far off so that it's not beyond the lifetime of the people who are interested in it," said John Hagga, another analyst at the Populatin Reference Bureau.
The Constitution requires a distribution of House seats as fairly as possible among the states, based on census data, every 10 years. For many years, the House of Representatives has been fixed by law at 435 members. That means that when one state gains a seat, another must lose one.
Last year, the Supreme Court ruled that this process - known as reapportionment - must be based on actual, raw population figures, instead of statistically adjusted data.
Those raw figures from the 2000 census will be released by Dec. 31, and the House seats will be reapportioned soon after. Mather's analysis projected reapportionment after this year and in 20 years.
Overall, eight seats could change states after this year's count, and 25 by 2020, Mather predicted.