House Vulnerability Index, post-2010 edition

If you were with us in the Swing State Project days, you might remember the House Vulnerability Index, which was a quantitative scheme I developed for assessing how likely House members were to be defeated in 2010, as something of a stopgap measure until we had enough information to start making race-by-race decisions. It turned out to be a pretty effective measure when run through stress tests (both in terms of using 2006 numbers to predict 2008 outcomes and 1992 numbers to predict 1994 outcomes) and we're finally getting around to examining how it did at predicting 2010 outcomes. The answer is: quite well. It pointed to losses by a handful of people who the polls and pundits never regarded as in much danger (Dan Maffei, Melissa Bean, Solomon Ortiz) while shrugging off some who were viewed as imperiled by the punditry but, in the end, weren't.

The method is described more extensively here, but the easy explanation is just that it rank-orders all districts held by a party both according to the margin of victory in the last election and according to the district's Cook PVI, adds those two rankings together and reorders them according to the added score. If the last result was a special election rather than a general, that's substituted into the scheme (which is important in terms of where Scott Murphy, Bill Owens, Mark Critz, John Garamendi and Charles Djou fit into things). Where a seat is an open seat, the margin of victory ranking is removed from the equation and substituted with a big fat 0, since the party in power is basically starting from scratch.

Here are the 78 most vulnerable Democrats according to the pre-2010 index, ranked according to vulnerability. The final column is the actual margin of defeat (or victory), so you can see who beat (or lagged) expectations relative to what the index might predict. Thanks to our sortability function, though, you can just click on the heading and see them arranged according to margin instead (or any other category). If you're wondering why 78, I copied over my final list of 75 from a year and a half ago, but had to add 3 more open seats that were nasty surprises late in the game (David Obey, Bart Stupak and Mollohan's primary defeat). Also, conveniently, that's for the most part where the losses stop. Red or blue shading means that the seat changed hands in 2010.

Ranking	District	Rep.	Margin rating	PVI rating	Vuln. Index	2010 Margin
1	AL-02	Bright	3	4	7	- 2.2
2	ID-01	Minnick	6	3	9	- 9.7
3	TN-06	Open	0	10	10	- 37.9
4	LA-03	Open	0	12	12	- 27.6
5	MD-01	Kratovil	5	11	16	- 12.1
6	WV-01	Open (Primary)	0	17	17	- 0.8
7	IN-08	Open	0	20	20	- 20.2
8	AR-01	Open	0	21	21	- 8.3
9	TX-17	Edwards, C.	21	1	22	- 25.2
10	TN-08	Open	0	30	30	- 20.2
11	NY-29	Open	0	35	35	- 13.1
12	MS-01	Childers	28.5	7	35.5	- 14.5
13	VA-05	Perriello	1	37	38	- 3.8
14	AR-02	Open	0	41	41	- 19.6
15	KS-03	Open	0	48	48	- 19.7
16	MI-01	Open	0	52	52	- 11.0
17	NY-20	Murphy, S.	2	52	54	- 9.8
18	VA-02	Nye	16.5	39	55.5	- 10.6
19.5	GA-08	Marshall	42	15	57	- 5.4
19.5	PA-10	Carney	38	19	57	- 10.4
21	PA-03	Dahlkemper	9	49	58	- 11.4
22	PA-04	Altmire	34	28	62	1.6
23	MI-07	Schauer	8	55	63	- 4.8
24	FL-08	Grayson	13	53	66	- 17.9
25	AZ-05	Mitchell	25	42	67	- 8.7
27	NM-02	Teague	36	33	69	- 10.8
27	NY-24	Arcuri	13	56	69	- 6.3
27	TN-04	Davis, L.	60	9	69	- 18.5
29	CO-04	Markey, B.	37	34	71	- 11.1
30	WA-03	Open	0	73	73	- 6.0
31	OH-16	Boccieri	30.5	47	77.5	- 10.8
33	AZ-08	Giffords	35	43	78	1.5
33	OH-15	Kilroy	4	74	78	- 12.9
33	NY-23	Owens	13	65	78	1.1
35	AZ-01	Kirkpatrick	48	31	79	- 6.0
36	ND-AL	Pomeroy	66	14	80	- 9.8
37	OH-18	Space	58	23	81	- 13.4
38	IN-09	Hill	56	26	82	- 10.0
39	WI-08	Kagen	22	61	83	- 9.7
40	NJ-03	Adler	15	69	84	- 2.7
41	TX-23	Rodriguez	40	46	86	- 5.0
42	PA-12	Critz	20	68	88	1.6
43	NC-08	Kissell	30.5	58	88.5	9.3
44.5	WI-07	Open	0	89	89	- 7.7
44.5	UT-02	Matheson	84	5	89	4.4
46	NH-01	Shea-Porter	19	71	90	- 11.6
47.5	FL-24	Kosmas	47	44	91	- 19.3
47.5	SC-05	Spratt	67	24	91	- 10.3
49	CA-11	McNerney	28.5	63	91.5	1.1
50	OH-01	Driehaus	16.5	77	93.5	- 5.5
51.5	FL-02	Boyd	64	32	96	- 12.2
51.5	NH-02	Open	0	96	96	- 1.5
53	NC-11	Shuler	69.5	27	96.5	8.6
54	PA-07	Open	0	98	98	- 10.9
55	FL-22	Klein	23	76	99	- 8.8
56	MO-04	Skelton	94.5	6	100.5	- 5.3
57.5	NV-03	Titus	18	83	101	- 0.6
57.5	NY-19	Hall	51	50	101	- 5.4
59.5	CO-03	Salazar	63	40	103	- 4.3
59.5	PA-17	Holden	74	29	103	11.0
61	KY-06	Chandler	87.5	18	105.5	0.3
62	MI-09	Peters	24	82	106	2.6
63	IL-14	Foster	45	62	107	- 6.3
64	PA-11	Kanjorski	10	101	111	- 9.4
65	TX-27	Ortiz	57	60	117	- 0.7
66	VA-11	Connolly	33	85	118	0.4
67	IA-03	Boswell	41	78	119	4.2
68	NY-01	Bishop, T.	49.5	70	119.5	0.3
69	NY-13	McMahon	75	45	120	- 3.4
70	SD-AL	Herseth Sandlin	107	17	124	- 2.2
71.5	OR-05	Schrader	46	79	125	5.3
71.5	CT-04	Himes	11	114	125	6.2
73	WV-03	Rahall	102.5	25	127.5	12.0
74.5	IL-08	Bean	61	67	128	- 0.2
74.5	PA-08	Murphy, P.	44	84	128	- 7.0
76	NY-25	Maffei	39	90	129	- 0.3
77	IL-11	Halvorson	65	66	131	- 14.7
78	NM-01	Heinrich	32	108	140	3.8

In terms of beating expectations, as you might have predicted, Tom Perriello certainly stands out, losing VA-05 by only 3.8 points; Chad Causey, the nominee in the open AR-01 race, also did well, keeping it within 8. Credit's due to Bobby Bright as well; his various acts of hippie-punching kept him in this thing, as polls up until the very end showed him in command and he only lost by 2.2. The most vulnerable Democrat to break into a double-digit victory was PA-17's Tim Holden, who has pretty much clinched his status as the closest thing the Democrats have to the Terminator (having previously been the freshman with the reddest district to survive 1994 and having survived a 2002 redistricting-based targeted extinction).

If you prefer your data in visual form, here's a scatterplot of the vulnerability index, graphed against the margin, showing a nice clean slope. (For those keeping score at home, the correlation coefficient is 0.59, with an r-squared of 0.35.) This is also helpful because, by looking at the distance of various candidates' dots from the red regression line, we can get an impression of who were the outliers (in both good and bad ways). Note that you can click on the graphic to get a more detailed view with labels for which dot represents which district.

As far as those who lagged expectations, looking at the distance from the trendline, Suzanne Kosmas in FL-24 and Debbie Halvorson in IL-11 look like the worst performers (excepting our sacrifical lamb in the TN-06 open seat) in the top tier, but we should also look at the few losses that came outside the list. Gene Taylor and Rick Boucher were unable to survive their district leans (they would have registered as vulnerable had they received more than a token challenge—as with Taylor—or any challenge at all—as with Boucher—in 2008), while Bobby Etheridge follows George Allen as the second ever political death-by-tracker. Jim Oberstar seems to be recipient of this year's Jack Brooks/Neal Smith Memorial Old-Guy-Caught-Napping Award, while Charlie Wilson seems to have lost by virtue of no one (me included) having any idea who he is.

Ranking	District	Rep.	Margin rating	PVI rating	Vuln. Index	2010 Margin
81	OH-16	Wilson	90	55	145	- 5.0
87	MS-04	Taylor	170	2	172	- 5.0
88	NC-02	Etheridge	112.5	60	172.5	- 0.8
107	MN-08	Oberstar	111	90	201	- 1.6
130	VA-09	Boucher	248	14	262	- 4.8
178	IL-17	Hare	248	98	346	- 9.6

That leaves Phil Hare alone at the bottom with my vote for the cycle's most epic fail. Granted, his apparent ineptitude at campaigning seems to have been camouflaged by having no opposition in 2008 (this quirk led him to appear as safe, statistically, as John Olver and Mel Watt), but he still managed to lose a 56 percent Obama district as a scandal-free incumbent by 9 percent.

Other Democrats who had close calls (less than a 10 percent margin) but weren't in the top tier of vulnerability include (listed with most vulnerable first) Chris Murphy (CT-05), Tim Walz (MN-01), Mike McIntyre (NC-07), Rick Larsen (WA-02), Joe Donnelly (IN-02), the open seat in RI-01, Dave Loebsack (IA-02), Ron Kind (WI-03), Dennis Kucinich (OH-10), Rush Holt (NJ-12), Carolyn McCarthy (NY-04), Sanford Bishop (GA-02), Bruce Braley (IA-01), Adam Smith (WA-09), Raul Grijalva (AZ-07), Lloyd Doggett (TX-25), Emanuel Cleaver (MO-05), Russ Carnahan (MO-03), Jim Costa (CA-20) and, believe it or not, Dale Kildee (MI-05).

Now let's take a look at how the index did at predicting Republican losses. (Yes, there actually were a handful of them, just as in 1994.) The pickups all fell easily within the top 10 most vulnerable. In fact, HI-01 should probably have been much higher in vulnerability given that Charles Djou won the seat with only 39 percent of the vote in the special election over two Democrats, which points to a flaw in the index. That margin rating is based on his 8.7 percent spread over his nearest competitor (Colleen Hanabusa), which is much better than many GOPers did in 2008, but that camouflaged his near-certain doom once he faced off against only one Democrat at a time.

Ranking	District	Rep.	Margin rating	PVI rating	Vuln. Index	2010 Margin
1	DE-AL	Open	0	3	3	15.8
2	IL-10	Open	0	4	4	- 2.2
3	LA-02	Cao	5	1	6	31.1
4	PA-06	Gerlach	9	5	14	- 14.2
5	WA-08	Reichert	16	6	22	- 4.2
6	HI-01	Djou	26	2	28	6.5
7	MI-11	McCotter	17	12	29	- 20.8
8	CA-50	Bilbray	11	24	35	- 17.7
9	FL-25	Open	0	36	36	- 9.6
10	MN-03	Paulsen	22	13	35	- 22.2

In case you're wondering, only four Democrats came within single digits of any Republicans who weren't on this top 10 list, which indicates how stiff the wind against the Democrats was in the 2010 cycle. They were Ami Bera in CA-03 (- 6.9 percent), Lori Edwards in the FL-12 open seat (- 7.0 percent), Steve Pougnet in CA-45 (- 9.4 percent) and Rob Miller in SC-02 (- 9.7 percent).

At this point, you may be saying, "That's nice from an academic standpoint, but what's in the past is in the past ... let's get on to who's vulnerable in 2012!" I'd agree, but 2012 is the first election after redistricting, and that will serve to scramble districts significantly to the extent that the Vulnerability Index will prove useless until we know the new PVIs for the new districts (and even then may not be useful, since margins from last time don't really carry over when a member might be facing a partly or mostly new district). Here are a just a few cases in point: Renee Elmers is theoretically one of the most vulnerable Republicans but will probably get a pretty safe seat out of redistricting, while conversely David Dreier is nowhere near this list but is probably busily picking out his parachute color right now. Nevertheless, for discussion purposes, the top 20 most vulnerable Republican and Democratic seats (under current configurations) are listed over the fold ...

Ranking	District	Rep.	Margin rating	PVI rating	Vuln. Index
1	OK-02	Open	0	2	2
2	KY-06	Chandler	1.5	3	4.5
3	IN-02	Open	0	13	13
4	PA-04	Altmire	8.5	7	15.5
5	AZ-08	Giffords	7	12	19
6	CA-11	McNerney	4.5	15	19.5
7	UT-02	Matheson	19	1	20
8	NY-01	Bishop, T.	1.5	19	20.5
9	NY-23	Owens	4.5	17	21.5
10	PA-12	Critz	8.5	18	26.5
11.5	CT-05	Open	0	29	29
11.5	NY-26	Hochul	20	9	29
13	VA-11	Connolly	3	27	30
14	GA-02	Bishop, S.	14	21	35
15.5	MI-09	Peters	13	26	39
15.5	MN-01	Walz	23	16	39
17	IA-03	Boswell	18	22	40
18	NC-11	Shuler	35	6	41
19	NC-07	McIntyre	32	10	42
20	NM-01	Open	0	43	43

Ranking	District	Rep.	Margin rating	PVI rating	Vuln. Index
1	NY-25	Buerkle	2	8	10
2	IL-10	Dold!	10	1	11
3	NH-02	Bass	7	6	13
4	NV-03	Heck	3	13	16
5	MN-08	Cravaack	8	9	17
6	WA-08	Reichert	15	7	22
7	IL-08	Walsh	1	27	28
8.5	NJ-03	Runyan	12	26	38
8.5	TX-27	Farenthold	4	34	38
10	OH-01	Chabot	25	14	39
11	PA-11	Barletta	37.5	2	39.5
12	NC-02	Ellmers	5.5	35	40.5
13	WI-07	Duffy	33	10	43
14	PA-08	Fitzpatrick	31.5	12	43.5
15	IL-17	Schilling	39.5	5	44.5
16	WA-03	Herrera	26.5	20	46.5
17	FL-22	West	36	15	51
18	MI-07	Walberg	17.5	38	55.5
19	PA-07	Meehan	52	4	56
20	IL-14	Hultgren	28.5	31	59.5

Worth noting: NY-26 would have had a vulnerability index of 86 going into the special earlier this year (0 + 86).