Monday, April 11, 2005

Delphi on the State House.

We will break the State House seats into three categories based upon their PVIs. An look at how the PVI (partisan voter index) that Mile High Delphi uses is available here. Basically, it is just a quick political handicapping tool that gives us a very general feel for how competitive the district is.

The three categories that we are going to break House seats down into will be Very Competitive (with a PVI below 5), Competitive (PVI between 5 and 10), and Non-Competitive (PVI above 10). This breakdown will give us a general feel for how competitive the House will be and what races we need to watch.

Dem Non-Competitive: HD 1-13, 24, 32, 34, 35, 41, 42, 46, 53, 61 and 62. Total 23.
GOP Non-Competitive: HD 14-17, 19-21, 38, 40, 43-45, 48, 51, 54, 57-59, 63 and 65. Total 20.

Dem Competitive: HD 18, 26, 36, 55 and 56. Total 5.
GOP Competitive: HD 25, 28, 37 and 60. Total 4.

Dem Very Competitive: HD 23, 29, 30, 31, 47, 50 and 64. Total of 7.
GOP Very Competitive: HD 22, 27, 33, 39, 49 and 52. Total of 6.

We will start out by looking at the "Sweet Sixteen." The Sweet Sixteen is made up of the sixteen most competitive districts. They are listed below from the most competitive to the least. From this we constructed our first prediction, which reveals how we have came up with our probabilities for who will control the House after 2006.

HD 52 PVI R - .00 2004 Results R 50.7% D 49.3%
HD 22 PVI R + .80 2004 Results R 51.8% D 48.2%
HD 27 PVI R + 1.04 2004 Results R 52.0% D 48.0%
HD 23 PVI D + 1.08 2004 Results R 49.9% D 50.1%
HD 33 PVI R + 1.67 2004 Results R 52.7% D 47.3%
HD 29 PVI D + 1.87 2004 Results R 49.1% D 50.9%
HD 47 PVI D + 2.76 2004 Results R 48.2% D 51.8%
HD 31 PVI D + 2.73 2004 Results R 48.3% D 51.7%
HD 50 PVI D + 4.12 2004 Results R 46.9% D 53.1%
HD 39 PVI R + 4.20 2004 Results R 55.2% D 44.8%
HD 64 PVI D + 4.72 2004 Results R 46.3% D 53.7%
HD 49 PVI R + 4.84 2004 Results R 55.8% D 44.2%
HD 30 PVI D + 4.85 2004 Results R 46.1% D 53.9%
HD 60 PVI R + 5.13 2004 Results R 56.1% D 43.9%
HD 56 PVI D + 5.69 2004 Results R 45.3% D 54.7%
HD 36 PVI D + 6.21 2004 Results R 44.8% D 55.2%

The sweet sixteen is made up of 7 GOP seats and 9 Democratic seats. Due to the record turnout last election (something on the order of 88%) and the fact that '06 is a midterm year, the Democratic tide that swept the state legislature last year will have difficulties increasing their holdings. If the 3% Democratic bump that normally accompanies presidential years is taken away the Democrats stand to lose at least 4 seats. Because of these factors, we put the probability of the GOP taking back the State House at 80%.

The State Senate has gone from GOP control in '98 to Dem control in '00, back to the GOP in '02 and back to the Dems in '04. Because of this, we will begin our probability of either party controlling the State Senate next year at 50%.

Those two numbers give you the projections that we currently have. GOP 40%, Dem 10% and Split Control at 50%.

I also found a few statistical points of interest.

Since the green party only ran in one House election, I focused my attention on the 17 races with a Republican, a Democrat and a Libertarian on the ballot. On AVERAGE the Republican got 13071 votes (47%), the Democrat got 13761 (49.5%) and the Libertarian got 928 votes (3.5%). Meaning, on average that the Libertarian vote would have to split seven votes Republican and two votes Democratic for the GOP to pick up those seats. ON AVERAGE. In reality, I only found one election where the Libertarian got a larger number of votes than the winning margin between the major parties (HD 23).

In the 31 districts where you had only a Democrat and a Republican on the ballot, on average the Republican got 15178 votes (51%) and the Democrat got 14525 votes (49%).

Perhaps the most interesting statistical fact was this. Each district should have a nearly equal population, and, all things being equal, you would think that having a 3rd party on the ballot would increase turnout. However, the average turnout for a race with three parties on the ballot was 27760, while 29703 turned out for the two party races. That is an increase of 7.2% on average. So it appears that, at least as far as these elections were concerned, the participation of 3rd parties lowered voter participation.

Cross posted at Polstate.

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