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Friday, January 8, 2016

Among Political Scientists, Sam Wang Trumps Nate Silver

Every few weeks or so Nate Silver or Harry Enten has a new discussion about Trump that ends exactly the same way-'He may just not win anywhere'-the belly flop theory. Ezra Klein also raises the hope that maybe for no particular reason, Trump will simply bomb everywhere. He'll lose Iowa then he'll lose NH and then that's all folks.

According to Klein, between now-January 8-and February 1, GOP voters are suddenly going to get serious.

http://lastmenandovermen.blogspot.com/2016/01/but-what-if-trump-does-win-nh.html

I always wonder why they always talk about what happens if Trump loses NH; the corollary question Klein and Silver never look at is what if he wins?

But just when I was ready to give up on political scientists-Nate Silver and friends-Sam Wang shows that they aren't all totally refusing to at least consider another possibility.

"The New Year is not a bad time for a fresh start. So please let me acknowledge that back in July, I was too pessimistic about Donald Trump’s chances. LikeHarry Enten, I was led astray by his high unfavorables. Six months into the Season of Trump, I think it is time to examine his chances with a more neutral stance."

http://election.princeton.edu/2016/01/05/what-december-polls-can-tell-us-about-the-gop-nomination/?platform=hootsuite

His favorables are now a lot better but Enten and Nate haven't noted that. Indeed, the reason why Trump won't win is constantly shifting. Now it's basically because it happened to Howard Dean in 2004 -he led and then he didn't, as happened to Rudy Giuliani in 2008.

Recently Enten went as far as claiming that Trump was in trouble because he's doing so well in national polls, he won't do well. This has been part of the anti Trump theory at Nate's place all along. Because Trump has done so well in national polls, they've spent a lot of time telling us that national polls are absolutely irrelevant. But now Enten went beyond simply claiming they don't matter to that they actually have negative predictive value.

A commentator-Amitabh Lath- at Sam Wang's puts it well:

"Frankly I never understood any of the “Trump is sure to fail” analyses. They involved all sorts of new variables like “unfavorables” and “ceilings” which I never quite got (and I suspect would not be hauled out if Jeb Bush had a similar numbers)."

"Furthermore, these Trump fail discussions have the whiff of desperate students: they think they know what the answer should be and throw in explanations and equations to make it come out they way it’s supposed to."

Yes, it's the same answer for ever shifting reasons that get me skeptical. Wang, argues on the other hand that when you look at Trump's numbers nationally, in Iowa, and in NH it puts him in some pretty good historical company.

"By this time in the past three Presidential elections, here is a table of how the eventual nominee ranked in national and early-state polls:"

YearNomineeNational#1-#2 leadIowaN.H.
2012 (R)Romney#18%#2#1
2008 (R)McCain#11%#2#2
2008 (D)Obama#219%#2#2
2004 (D)Kerry#47%#3(#1)
2000 (D)Gore#120%(#1)(#1)
2000 (R)G.W. Bush#145%(#1)(#1)

"For national polls, I show late-December/early-January polls. The “#1-#2 lead” column shows the median difference between the #1 and #2 national candidates. Because the Iowa and New Hampshire elections are four weeks later in 2016 than in past years, in those cases I used data from the first week of December. Finally, where polling data was missing, the nominee’s final election outcome is given in parentheses."

"In nearly all cases, the eventual nominee has gotten enough attention and support to finish in the top two. Second place is not a bad spot to be in: in this data set, the eventual nominee was at #4 once, #3 once, #2 six times, and at #1 five times"

"Although the amount of data is scanty, it should also be noted that although the Democratic and Republican races in 2000 were nominally open, each had a clear national leader: Al Gore by 20%, and George W. Bush by 45%. Therefore their #1 rankings were highly predictive. In the other races, the national leader was ahead by only 1% to 8%, and the candidate at #2 was slightly more likely to prevail in the end."

This certainly defies Enten's innovative claim that leading in the nationnal polls in January is somehow tragic.

"Now, look at the 2016 campaign. Here are current standings for Republican candidates who are likely to be invited to the January 14th debate:

CandidateNationalIowaN.H.
Trump#1#2#1
Cruz#2#1#3*
Rubio#3#3#2
Carson#4#4#7
Bush#5#6#6
Christie#6#7#3*
*New Hampshire polls currently show Cruz and Christie within one percentage point of one another.
"The only candidate with all #1 and #2 rankings is Donald Trump. Therefore, if 2016 were to follow the pattern of past elections, he would be the most likely nominee. After Trump comes Cruz, followed by Rubio as a long shot. Nobody else fits the pattern."

"How commanding is Trump’s advantage? Here is his position relative to past nominees:"

YearNomineeNational#1-#2 leadIowaN.H.
2000 (R)G.W. Bush#145%#1*#2**
2016 (D)H. Clinton?#122%#1#2
2000 (D)Gore#120%#1*#1*
2016 (R)Trump?#120%#2#1
2008 (D)Obama#219%#2#2
2012 (R)Romney#18%#2#1
2004 (D)Kerry#47%#3#1**
2008 (R)McCain#11%#2#2
**These values indicate final outcomes.
"For comparison I include Hillary Clinton, this year’s overwhelming favorite for the Democratic nomination. This emphasizes the fact that based on polling data, Donald Trump is in as strong a position to get his party’s nomination as Hillary Clinton in 2016, George W. Bush in 2000, or Al Gore in 2000. The one case in which a lead of this size was reversed was the 2008 Democratic nomination, which very was closely fought."

"Now he Sam Wang makes a very good point-something that Enten and Nate, and Ezra Klein seem to rule out-that this could be a year of realignment in the GOP-the year the Establishment doesn't decide. Nate Silver has emphasized that ok, maybe the party doesn't always get its favored candidate but it surely can stop someone they are as opposed to as Trump. Usually this is true-but they didn't in 1964. Why can't 2016 be like 1964?"

"Obviously, polls are not the entire story of the campaign. Unlike past nominees, Trump does not have the national party behind him. In that respect, he is emblematic of the overall weirdness of this year’s GOP primaries."

"Other factors are said to influence the nomination process: candidate experience, campaign finance, and party endorsements. These are described in the New York Times feature Who’s Winning the Presidential Campaign? (Here is one entertaining recent discussion over at FiveThirtyEight.) In my view, these factors are likely to matter under normal conditions – until a political party undergoes a major upheaval. That happens about every 40-50 years (see this excellent XKCD explainer graphic). Trump-as-nominee could fairly be seen as such an upheaval. This is one reason to pay attention not just to data pundits, but also to grizzled old historians."

It will be interesting to see if Nate/Harry Enten respond to Wang-who is one of them. I tell you, having Trump win in NH will be all the sweeter to see the egg on their faces.



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