There is nothing like leadership chatter to help draw some punters back to the Federal election betting market…

In particular, Labor’s price has been improving a little bit over the last 72 hours at Centrebet. At the time of writing, Labor is at 4.80 to the Coalition’s 1.17 (implied probability of ALP winning = 19.6%), in from 5.60/1.13 (16.8%) as recently as 5pm Monday March 18:

Labor had been out on 5.90 to the Coalition’s 1.12 as recently as March 12.

At sportsbet, the Labor leader market has Gillard out to 2.50, Rudd at 1.50. Factoring in the other Labor leader possibilities, this equates to a 44% chance that Rudd is leader at the next election. As recently as March 9, Rudd was at 2.35 (30% probability) and Gillard at 1.60 (44% probability).

…a bit of volatility around the time of the announcement itself, but settling down to Labor’s price easing slightly. See the graphs at the top of the blog or click on the link.

And not much action in the wake of the resignation announcements etc.

Labor at 4.05 on Centrebet to the Coalition’s 1.23, for an implied 77% probability of a Coalition win.

Stick a fork in it, I reckon. Done. And done.

This happens to me so often. I’ve developed a Pavlovian hesitation when reaching for my laptop after its been through the X-ray scanner.

I wonder if its socks interacting with floor or something, since I’m usually still shoes off when it happens (I think).

Anyway… Ouch.

Just another thing for the TSA people to giggle at…

Here are two quick looks at the roll call last night from the House of Representatives, concurring with the Senate amendments to HR8. This was the so-called Fiscal Cliff vote, roll call 659 of the 2nd session of the 112th U.S. House of Representatives.

I’ve plotted the Ayes and Noes against each representative’s “ideal point”, a summary measure of each representative’s voting history based on previous roll calls in the 112th House, usually interpreted as an estimates of each legislator’s “left-right” or liberal/conservative ideological position. Democrats are shown in blue (and cluster to the left of the graph); Republicans are in red, on the right.

Notably, Speaker Boehner voted Aye, just the 9th time he has recorded a vote in the 112th Congress, which is not unusual for Speakers. With such a short, a largely one-sided short voting history, the algorithm puts Boehner out on the right-hand tail of the ideal point distribution. Majority Leader Cantor voted Nay.

The 1st graph shows a probit curve overlaid on the points, an estimate of the probability that a legislator occupying a particular point on the left-right continuum votes for the measure. Since all but 16 Democrats voted for the measure, the curve falls as we move from left to right across the page.

The 2nd graph fits probit curves separately for each party. The interesting action is among the Republicans, with the vote cleaving Republicans 151 – 85, and largely along ideological grounds. The ideal point estimate predicts Republican voting on this measure reasonably well (AUC = .816, Brier = .166).

In addition to being a rare instance of the Speaker casting a roll call vote, it is also an even rarer case of the Speaker voting against the majority of his party, including the majority leader. It might be a nice exercise to see when this last happened. We’ll see if this costs Boehner his job as Speaker; I suspect not.

Obama won the 2012 election by keeping the swing small where it needed to be kept small. Just two states changed hands: Indiana and North Carolina, both won narrowly by Obama in 2008.

But consider this. Florida, Ohio and Virginia were all won by Obama in 2008 on margins smaller than the 53.4-46.6 national margin. Obama kept them all in 2012, with swings smaller than the national swing. Details…

Nationally, the two-party swing against Obama is currently -2.11 percentage points: that is, Obama beat McCain in 2008 53.4-46.6; at this stage of the 2012 count he is winning 51.3-48.7.

Let’s look at some key swing states.

• Ohio (18 Electoral votes): Obama won it 52-48 in 2008 (in two-party terms). A two percent swing and Romney wins it. The swing is only -1.12, about half the national swing. Obama wins Ohio 51-49.
• Florida (29 EVs): Obama won 51.3-48.7 in 2008. A 1.3 percent swing against Obama would see the state fall to Romney. The swing appears to be -0.83 points with Obama winning 50.4-49.6.
• Virginia (13 EVs): Won by Obama 53.2-47.8. Romney needed a -3.2 percentage point swing against Obama to win the state. He got half way, -1.6 points, and the state stays with Obama.
• North Carolina (15 EVs): Obama outpolled McCain by 13,700 votes in 2008, to win 50.2-49.8. The swing was -1.26 points and Romney wins 51.1 of the two party vote.

And on it goes. Without more of these easier states coming over the line, getting to 270 was a very difficult proposition for Romney. The Romney campaign would have needed some large swings in other battlegrounds to get close.

• Iowa: Obama had a 4.7 point margin, the swing to Romney was 1.8.
• New Hampshire: 4.8 margin, a 1.9 swing.
• Colorado: a 4.4 point margin, a 2 point swing.
• Wisconsin: a 7 point margin, a 3.6 point swing (larger than the national average, and larger than the swing-state average swing, thanks Paul Ryan?).
• Nevada: a 6.3 point margin, a 3 point swing.

And Pennsylvania? Forget it. With 20 Electoral College votes you can understand why it is an enticing target. But Pennsylvania was higher up the tree than Iowa, New Hampshire or Colorado, breaking 55.2-44.8 in 2008. Romney won a 2.6 point swing in Pennsylvania (slightly higher than the nationwide swing), but still only half of what he would have needed to win the state.

Indiana was the other Romney pickup. Obama’s 50.5-49.5 victory there in 2008 was a shocker, coming on the back of 10.9 point swing: to understand how big that was, recall that the national two-party swing to Obama was 4.8 points in 2008. Indiana was never on anyone’s battleground list in 2012. Expectations were that Indiana would “revert to type”. Absent any serious attempt to defend the narrow and unexpected 2008 win from the Obama camp, Indiana swung 5.8 points in 2012 (more than twice the national swing) with Romney winning 55.3-44.7.

A similar logic applies to Missouri, which Obama almost won in 2008, falling short by 0.06 of a percentage point, outpolled by McCain by just 3,600 votes. Missouri “reverted to type” in 2012 too, with a 4.8 point swing. In fact, Obama’s 2012 showing is worse than Kerry’s in 2004 (45.1% of the two party vote, versus Kerry’s 46.3%).

Two graphs summarize all this; clicking on each will open a larger version in a new browser window.

The first is a dot plot showing the swings in order. The color shows the disposition of the state in 2008. Two vertical bars show the national swing and no swing. Open plotting symbols for swing states show the swing they would have required to change hands: for North Carolina, the open plotting symbol lies to the right of the actual swing (the swing exceeded Obama’s 2008 margin). Again, note how the swings against Obama come up short in the other battleground states.

Second, a plot of 2012 swing against 2008 result. Shaded regions denote politically distinct regions: (1) Obama retains, where the 2012 swing isn’t enough for the state to fall to Romney, with 27 states in this category; (2) Obama losses, where the swing against Obama is enough for the state to fall to Romney (Indiana and North Carolina); (3) Obama gains (a null set in 2012); and (4) Republican retains, with 22 states in this category. The District of Columbia is excluded from this graph. The size of the plotting symbol is proportional to the state’s Electoral College votes; color indicates 2012 disposition; the national result is shown with a dark point labelled “USA”.

Obama wins the election on the back of that set of states that sit just to the right of the 50-50 threshold on the horizontal axis, but that didn’t drift down on the vertical “swing” dimension into the “change hands” cone.

I tweeted earlier that the correlation between 2012 and 2008 state-level, Democratic, two-party vote shares is .982. Take out (the outlier) DC and this goes down to .976.

Here’s another look at the data, comparing 04, 08 and 12. More on this later (as well as overlaying the national two-party vote shares), but we have stories that go along with Alaska, Hawaii, New Jersey (!), Utah, over these three elections.

What is striking is how the swing stayed small where Obama and Co. needed it to stay small. Big swings against them in Indiana and the South didn’t matter.

I’ve had numerous requests for various outputs from my model, so I’ll put them up here.

1. Forecast win probabilities for Obama, by unit, by day. These were the quantities also requested by a group of researchers working at Penn, who will use Brier scoring to assess various probabilistic forecasts of the state-by-state outcomes.

A summary of how well the final (Election morning) state-by-state probabilities performed is shown in the attached graph, which plots Obama 2-party vote share (using data from this afternoon from AP) against the probabilities from my model.

The probabilities are the data I’ve presented in this graph:

The data themselves are here (CSV). The final set of probabilities also appear in the file I link to below.

2. State level predictions, Obama 2-party vote share, plus uncertainty assessments. The comparison with actual state-level outcomes appears in the following scatterplot (the diagonal line is a 45 degree line).

Data here (CSV). One of the columns is the final probability of Obama win, if you are looking for that.

It isn’t really a fair comparison, since there isn’t such a thing as “US election administration.”

Rather, like national elections themselves, there is a “rich tapestry” (um “wild riot”?) of state and county level election administration systems in the United States, with much variance in law, technologies, budgets, professionalism, partisanship and traditions.

Annabel Crabb takes a light-hearted look in this SMH piece, teasing a Foreign Correspondent story (ABC TV). I’ve been banging on about this for years to Oz journos etc; Australians ought to better understand and appreciate the minor admin miracle that the AEC is.

Peter Brent (@mumbletwits) wrote a PhD dissertation (big PDF) that took a solid look at the historical background, how Australia came to get something like the AEC (inter alia). I’ve long thought “it wus compulsory voting wot dun it“: that professional, standardized, centralized, election admin is a consequence of enacting a national-level compulsory voting statute in the 1920s. But last time we corresponded on this (a comment on my blog) Peter said his dissertation research found that Australian election admin was headed in this direction ahead of CV.

At the risk of flattering Brooks, his rant re Nate and probabilities did remind me of Edmund Burke howling at the moon:

…the age of chivalry is gone.

That of sophisters, economists; and calculators has succeeded; and the glory of Europe is extinguished forever.

from Reflections on the Revolution in France.

Re-posting what just appeared on HuffPost:

On the eve of the 2nd presidential debate, it is helpful to take stock of what current polling is indicating about the campaign.

Romney’s debate bounce – or rather, Obama’s debate slump – appears to be over. National-level polling appears to have bottomed out for Obama. Further, once we integrate the information about the national trend contained in the state-level polls, it appears that Obama’s post-debate slump was not as large as it might have seemed at the time (and I’m talking to you, Andrew Sullivan). Indeed, with the benefit of only a little hindsight (and only a little modeling) it appears that only about 1.5 percentage points separate Obama’s late September, national peak from his early October trough, with a recovery of a few tenths of a percentage point over the last 7-10 days.

Indeed, at the national level, it appears that even in the immediate aftermath of the 1st debate, Obama never trailed Romney, once the information in the state level polls is integrated with the national-level polling.

All the same, the national race is unquestionably tighter now than it was. Obama’s lead in the national track produced by my model is about half a percentage point. In late September this lead was four percentage points.

The swing state picture has generally remained better for Obama. In the picture below I look at the the national-level estimate of Obama’s two-party share, along with results from 9 battleground states, all won by Obama in 2008. A useful reference point is Obama’s two-party share in 2008, appearing on the left of the graph. In the middle of the graph I plot the estimates from my model using polls fielded prior to the 1st debate.

The general fall in Obama support between 2008 and where the campaign stood on the eve of the 1st debate is clear (the pattern of lines sloping down, left to right). Only in Ohio was Obama generally outperforming his 2008 result.

Since the debate, Obama’s national vote share has slipped by roughly the same amount it had fallen between the 2008 election and where it stood on the eve of the debate: from 53.7% to 52.2% (pre-debate) to 50.4% (now). Post-debate slumps of a similar magnitude appear across the nine battleground states on the graph. North Carolina now lies on 48.5% (Obama’s share of two-party vote intentions). Florida had been resisting the national trend away from Obama prior to the debate, but has also fallen below 50%. Virginia is at 49.9%. At this stage, only Indiana, North Carolina and Florida look like they will be picked up by Romney, which won’t win Romney the election.

Obama won Ohio with 52.3% of the two-party vote in 2008. Pre-debate, I estimated Obama two-party support there at 53.4%. Today that figure is 51.5%, with the falls relative to both the 2008 result and the pre-debate estimate the lowest among the swing states. Relative to 2008, Obama is off 0.8 percentage points in Ohio; the corresponding numbers are 1.7 in North Carolina, 2.1 in Florida, 2.9 in Iowa, 3.3 in Virginia (the same as the national-level swing), 3.9 in Colorado, 5.1 in Wisconsin, and 5.3 in Nevada.

So long as Obama’s Ohio numbers hold up, so too will his chances of winning the Electoral College, and thus far, they have. Music to the ears of owners of Ohio’s television stations…