[UPDATED] If you aren’t a numbers geek, …

…you can probably skip this post. On the other hand, I think there might be one or two HA readers who will find this intriguing.

At a special meeting later this morning, the Washington State Redistricting Commission will unveil the next iterations of their proposed redrawing of Legislative District boundaries. As displayed here (PDF), the Commissioners have split into two bipartisan pairs, each responsible for drawing a particular portion of the state. Commissioners Tom Huff (R) and Dean Foster (D) have been working on the Olympic Peninsula, the Pacific coast, and the southern section of the wet side of the state. Their colleagues Tim Ceis (D) and Slade Gorton (R) have been tasked with working on the Eastside, the islands, and the northern west-of-the-Cascades area. They are not currently dealing with either the Seattle environs or the large area east of the mountains.

I don’t know whether they’ve been skipping over both the most and least urban parts of the state because they’ve already agreed on the LD lines in those areas, or because they’re at an impasse there, or (most likely IMHO) because drawing the lines in and around Seattle and the dry side depends on the outcome of their deliberations in the segments they’re working on. Whatever the reason, the Commissioners had better get their asses in gear — they’re supposed to present an agreed-upon plan to the Legislature by January 1, 2012, just half a month from now.

While this next presentation will be the third iteration of LD borders, we still have seen no Congressional District maps since each of the four Commissioners presented their own proposals on September 13, fully three months ago! Their silence on the topic frustrates many observers no end.

While we wait (and wait, and wait, …) for the Commissioners to break their long silence, I’d like to take a step back in the process, to discuss the reapportionment that presented the Commission with the opportunity to construct a brand-new Congressional District instead of merely rejiggering the existing ones in their redistricting task, as they’re doing with the state’s 49 (no more, no less) Legislative Districts.

As you’re no doubt aware, the number of Congressional Districts in each state is determined based on the results of the decennial Census, mandated by the Founders in Article I, Section 2 of the Constitution and revised under the 14th Amendment (you know, the one that got rid of that pesky three-fifths of a man thing). How the reapportionment is actually carried out is based on laws written by Congress, and those laws have changed numerous times over the decades. I’ll mention three issues to be considered:

• The Census counts persons, not citizens. Undocumented individuals, if they’re willing to participate, count as residents of their state.
• The apportionment population is not the same as the resident population. The latter does not count federal employees (including the military) living overseas on April 1. For apportionment (but not redistricting) purposes, such individuals are counted with their state of residence as listed on their employment records. This approach can make a difference in apportionment of Congressional Districts … in 2000, Utah might have gotten an additional seat if the Census counted Mormon missionaries for apportionment; that seat went instead to North Carolina, and Utah took its case (Utah v. Evans) all the way to the Supreme Court, where UT lost.
• Sensibly, apportionment is carried out through the use of a ranking algorithm. What isn’t set in stone is the methodology. It’s been done in a variety of ways over the years. Different procedures often give different results, but it must be said that there is no “correct” way to do it. Whatever method has Congress’s blessing at the time is the method to be used.

Washington’s resident population in the 2010 Census is 6,724,540. Adding in the 28,829 Washingtonians overseas, the state’s apportionment population is 6,753,369. Washington has the 12th highest count of overseas residents, one place better than its overall population rank. Texas, #2 overall, has the highest number of overseas persons, while California ranks third (behind Florida). Alaska, way down at #47 in population, ranks 26th in overseas employees.

Since 1940, the method of equal proportions has been used for reapportionment. After each state receives the required minimum of one seat, the other 385 seats are assigned to states in descending order of priority value (PV), where PV for potential seats 2, 3, 4, … is calculated as:
where n is the state’s potential seat number. In other words, the PV for a state’s second seat is its apportionment population divided by the square root of two. For its third seat, divide by the square root of (3*2=)six, then continue with the square roots of (4*3=)12, (5*4=)20, 30, 42, and so forth. By the time we get to the 55th seat, the divisor is the square root of 2970 (that’s 55*54). After all these values are calculated, rank-order them in descending order and assign the seats until 385 of them have been filled.

Not surprisingly, the 51st seat goes to the largest state, California. Texas gets #52, followed by another CA seat, then NY, FL, CA again, TX again, and so on. Washington’s first added seat (its second overall) is #78 and its next is #122. The state’s ninth seat, equalling its 2000 number of Representatives, comes in at #391.

It gets really interesting as we come to the final few seats. The assignments for the last ten seats (#426-#435), along with the next ten near-misses, are displayed below:

The new WA-10 seat comes in at #432, comfortably above the cut-off. Minnesota’s eighth seat wins the final position in the House (too bad, as it’s likely that Michelle Bachmann’s district would have been axed). MN just barely avoided subtracting a seat from its 2000 allocation. At #434, California narrowly averted losing a seat in the House; if the Golden State had done so, it would have been its first-ever lost seat. Washington, by the way, has never lost a seat either. It may be poetic justice that North Carolina is the first runner-up this time around, after winning the final spot in 2000. The Tarheel State missed adding another seat by that thin margin.

It turns out that using resident population instead of apportionment population wouldn’t have altered the composition of the next Congress. The rank-order of the last five seats would be different, with Washington at #433 and TX-36 taking the final spot.

It’s likely that none of the above is of much interest to the Redistricting Commission. They probably don’t particularly care how it came to pass that they’re tasked to draw ten CDs instead of nine. It falls to reapportionment geeks like me to look at this sort of information. There’s a pile of additional information here that I find fascinating — trends in the distribution of House seats over time, states that actually lost population between Censuses (hint: several states in the plains in the 1930s … can you say “Dust Bowl”?), states that have never lost seats, states on long seat-losing streaks (Pennsylvania has lost at least one seat in every Census since 1930), and much more.

If you’re interested enough in redistricting, tune in to the Redistricting Commission’s web feed at 10:30am. It won’t be great theater, but the final result of all that line-drawing and all that negotiation will affect your political life for a decade. And whether you know it or not, that’s important.

[UPDATE, 1:30pm]

An item I meant to include in the original post — Washington wasn’t even close to reaching 10 seats in the 2000 Census. Its ninth seat came in as #407, and the next potential WA seat (#455) missed the cut by 20 positions.

The third iteration of draft LD maps, in PDF format, is now available at the WSRC site.

A couple more (way-cool, IMHO) links from the Census website:

• Apportionment methods and factors considered, from 1790 to the present
• How various apportionment methods can produce differing allocations, with examples

Video “explanation” of the apportionment process, from the Census Bureau: