Actual Vote Margin by Pre-Election Trend Estimate
Charles Franklin | November 5, 2008
The plot shows the relationship between our pre-election trend estimate and the vote margin. These are not quite complete data but as of 8:20 AM Wednesday. But I don't expect large changes. DC is omitted because there was virtually no polling there.
Which states are which you ask? Behold:
How about quantifying the errors? Here is the distribution with descriptive statistics in the plot.
So on average we missed the margin by less than half percentage point. Most states we got within five points. And a few we missed b more than five points on the margin (or two and a half points or more on each candidate.)
We'll be doing lots more looking at poll performance and how our estimators succeeded and where they failed. But probably not before a nice restorative nap.
Comments
I made a similar scatterplot using RCP's numbers and found the same thing: the predictions tended to underestimate both McCain's support in red states and Obama's support in blue states; in the swing states, it was awfully close.
Posted on November 5, 2008 12:55 PM
And it's worth noting, by the way, that on the scatterplot, you can consider anything in the upper-left or lower-right quadrant to be a true red-to-blue or blue-to-red "surprise." NC's right on the line, so Indiana's really the only one.
Posted on November 5, 2008 1:01 PM
I'm wondering if the high variance in the very blue and very red states was likely a consequence of the relatively few surveys there, thus allowing methodological errors of a few polls to underestimate the results. Of course, I suppose that they could have overestimated the results as well, so it's interesting that they tended to make it more of a "horserace" than it really was.
Posted on November 5, 2008 2:12 PM
There's one oddity in the election returns so far. Stevens was 20 down in the recent poll after his conviction and now may have won re-election. Anyone have a reason for this?
Posted on November 5, 2008 2:15 PM
I agree with cinnamonape -- the fewer polls (because the state is not a battleground), the less reliable the consensus.
Posted on November 5, 2008 2:25 PM
@RWCOLE:
Maybe the Republicans suddenly realized that a vote for Stevens was most likely a vote for a special election (assuming the Senate chucks Stevens out) that might be won by a different R.
Posted on November 5, 2008 3:24 PM
I am also curious about the Stevens victory in Alaska. He was down a few points in the polls and if I remember correctly the last poll before the election showed him down about 8-10 points. Did Palin go up to Alaska to help fix the machines. I would like to see exit polls seeing who they voted for and compare it to the result. I smell something here. If he was kicked out of the Senate she could appoint herself Senator a much better position going forward to the 2012 election.
Posted on November 5, 2008 4:42 PM
@gerald
I truly doubt there was a conspiracy... I think Alaska is just a particularly idiosyncratic state that is a little more difficult to poll accurately. Particularly when the average Alaskan may feel like the lower 48 are treating them as the butt of some sort of Palin/Stevens/Young joke, they may have just decided to stand up for their fellow Alaskans at the expense of voting for a convicted felon.
Posted on November 5, 2008 4:55 PM
One more point - about Georgia. A substantial number of early voter results from Fulton and Gwinnett Counties are still uncounted. That could be as many as 275,000!
http://www.11alive.com/news/local/story.aspx?storyid=123175&provider=top
Posted on November 5, 2008 6:56 PM
zealotus says: "Particularly when the average Alaskan may feel like the lower 48 are treating them as the butt of some sort of Palin/Stevens/Young joke, they may have just decided to stand up for their fellow Alaskans at the expense of voting for a convicted felon."
Hmm, perhaps. But if that's the case it is just going to lead to Alaskans being the butt of even more jokes.
Posted on November 5, 2008 8:50 PM
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