Nate Silver Whiffs on Montana’s US Senate Race & Other Stuff
by Jay Stevens
Hey, everybody! I thought I’d drop in and say hello and give shouts out to old friends that did well in their election bids yesterday. Jhwygirl and I chatted on the phone the other day, and she said I should post every once in a while, and why the heck not? I miss Montana politics and the hubub of election day in Missoula.
So, anyhoo. Congrats go out to Jon Tester and Steve Bullock, who won very close and extremely important races. Congrats, too, to Linda McCulloch for destroying Brad Johnson, again. (Who will ever forget Johnson botching the 2006 election? Not Montana, apparently.) And to Monica Lindeen in defeating the reality-challenged Derek Skees. (Who won 46 percent of the vote?) Tim Fox‘ win in the attorney general race, and the nearly neck-and-neck OPI race should remind us how nuts and frustrating Montana election results can be. Do folks really like Fox’ dirty politicking? And why would anyone support Juneau’s excellence in public office with a vote for Welch? (Please speculate freely in the comments!)
Congrats, too, to old friends JP Pomnichowski, Bryce Bennett, and Ellie Hill for winning their races. And my sympathies for Richard Turner — a great guy and good friend who deserves a seat in Helena, even if his neighbors don’t see it. I wish someone had written more about the state races this year — I used to do it, and enjoyed it. Anybody want to analyze this year’s results?
What I really came here to talk about, though — me and everyone else, apparently — is Nate Silver. Yes, we all know about the punditry backlash, the dust-up with Joe Scarborough, and the fact that Silver nailed it. (I’m with Conor Friedersdorf: I trust Silver more because of the bet.) Okay, Silver might have destroyed punditry (um, no), but he’s not perfect: He muffed Montana.
Read it again: Nate Silver got Montana’s US Senate race wrong.
Actually, he missed it by quite a bit. Silver projected that Dennis Rehberg would win the race, 49.9 percent to 48.4. Tester, according to the unofficial results, won 48.5 percent to 44.9. That’s a swing from a +1.5 Rehberg win to a -3.6 Rehberg loss, over five percentage points off from his projection. The odd thing is that recent polls showed Tester with a small lead — even Rasmussen, which tended to overestimate Republican support. How did Silver interpret those results with a “lean Republican” projection?
The big factor in his analysis was an adjustment he called “state fundamentals,” which, according to the blog, is “an alternative forecast of the outcome that avoids polls and instead looks at the partisan environment of a state, public fundraising totals, statistical measures of left-right ideology and candidate quality, and other quantifiable factors.” According to that measure, Rehberg had a 50.7 to 42.2 percent lead.
That was egregiously wrong.
Why? For starters — and I’d need to check other states’ election results over the years to confirm this — Montana is notorious for splitting its ballots. Montana’s perfectly comfortable, for example, in voting for a Republican president, whisking in Democrats to all the statewide seats, and increasing the number of seats Republicans hold in the state legislature — all in the same election, which happened in 2008. This year, Montanans went for a Republican president, Democratic governor, and Democratic Senator, while dividing the statewide seats.
For another, Silver apparently didn’t calculate the effect of a third-party candidate. This election Libertarian Dan Cox won a whopping 29,979 votes, good for 6.52 percent of the vote, which is nearly double Tester’s margin of victory. That’s reminiscent of 2006, when Libertarian Stan Jones’ vote haul (10,377) was more than Tester’s margin of victory over Conrad Burns (~3,500). Tester, after all, won a smaller percentage of the electorate in 2012 than he did in 2006. It’s just that Montanans apparently dislike Dennis Rehberg even more than they did Conrad Burns — after his disgrace for his involvement in the Abramoff corruption scandals.
Either way, Silver’s election projection model is good, but it ain’t perfect.