Posted on 01/31/2016 12:04:23 AM PST by Cincinatus' Wife
The final Des Moines Register poll was just released, showing Donald Trump leading the Republican field in Iowa with 28 percent, Ted Cruz with 23 percent and Marco Rubio with 15 percent. Hillary Clinton was ahead of Bernie Sanders, 45 percent to 42 percent, on the Democratic side. The political world - us included - was eagerly awaiting this survey, as Ann Selzer, who has conducted the Register's polls since the 1988 caucuses, has a very good track record. But just how predictive of the final results have Selzer's polls been? History suggests they're a good indicator of what will happen in Monday's Iowa caucuses, though there is room for a candidate or two to surprise.
I've gathered Selzer's final caucus polls for Republicans and Democrats since she started at the Register. For each race, I've calculated the difference between all candidates' polled percentage of support and their final share of the vote.
Selzer's final poll has correctly projected every single winner except for Republican Rick Santorum in 2012.
And the Register poll's successes haven't been limited to blowout races. She caught the late momentum for Democrat John Kerry in 2004 and famously called Barack Obama's victory in 2008.
Even when Selzer's final poll missed the winner in 2012, it still indicated the potential for Santorum to win. The survey was conducted over four days, and in addition to the topline, aggregate numbers, Selzer released day-by-day results. The final day of her last 2012 caucus poll showed Santorum within a percentage point of Mitt Romney. In fact, the average error per candidate of the last day of her final 2012 caucus poll was just 1.9 percentage points.
Indeed, what makes Selzer truly special isn't just that she calls winners but that her error rates are fairly low across all candidates. Her average error per candidate per year has been just 3.3 percentage points. That means that what a candidate receives in her poll is probably going to be pretty close to what he or she gets from voters.
That's not to say the Des Moines Register poll is perfect. It sometimes misses on a candidate by a lot. Selzer's final poll in 1988 missed Republican Pat Robertson's eventual vote share by just more than 10 percentage points. Same thing with Kerry in 2004.
Who might benefit from that type of miss this time around? History suggests there are two types of candidates who tend to outperform their polls. The first is a candidate who does well among Christian conservatives. Selzer's final polls on the Republican side in 1988, 1996 and 2012 all missed the candidate favored by Christian conservatives by at least 8.5 percentage points. That could be good news for Cruz. Secondly, candidates with late momentum, such as Kerry in 2004 and Santorum in 2012, also tend to beat their polls. That could be beneficial to Rubio, who seems to be gaining in some polls.
Could there also be a big error on the Democratic side? It's possible, but Selzer did particularly well in 2000, the last Democratic campaign with only a few candidates running. Fewer candidates means voters have an easier time settling on one candidate and reallocation of support becomes less of an issue.
Of course, we won't know how accurate Selzer's final poll is this year until Monday or the day after. It's worth remembering, however, that even the best pollsters - and Selzer is one of the best - aren't perfect.
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Go Canada!
As someone who has found CW's 4 a.m. posts in favor of Rick Perry and Gov. Walker surpising, even amazing, in anyone not a fulltime campaign worker (and said so, saying further that I thought she was one), and as a disappointed former Rick Santorum supporter and now a Sen. Cruz supporter ...... bump.
No need for people to go nuclear in here except when an obvious 'Rat troll or gay/Communist Mau-Mau or Stormfront troll is spotted, and we're a long way from that in talking about preferred candidates in a surprisingly candidate-rich, insurgent-rich Republican primary season.
I'm a lot more like Mr. Wonderful than one of those rabid Ewoks over at DU, but I wouldn't bite CW for not supporting Ted Cruz or Rick Santorum. Our midpack candidates are light-years better than the other bunch's best (get a net), and the leaders are better still, and might harbor (yes, I dream of it) another Ronaldus Magnus (PBUH).
Scripsi, scripsi.
You have to do it with a head shot. Body shots won’t do it.
The little idiot just said CW only posts anti-Trump stuff.
What a maroon. Maybe that’s because she is for Ted Cruz and still sane.
I don’t reply to anyone whose posts reveal their IQ’s to be below 80...it wouldn’t be right.
That story was interesting. Everyone should click on it.
It is revealing of what we already kinda knew and certainly suspected.
The Donald does not like women or see them as equals.
Yes, what you say is true.
But CW has been patient, factual and polite while the other creature can only exceed herself in nastiness.
CW should stop answering him/her.
A gentle reminder: you don’t have to be here.
Oh, it is sad how the Trump people simply CANNOT refrain from personal attacks. I have been the recipient of many.
It will be hard to see those people as friends in the future, whatever happens.
Good analysis.
You might not want to count to heavily on those votes going to Cruz just yet
I would not be surprised if Rubio wins, or finishes a strong 2nd, tonight.
According to polling a plurality of Iowa voters are either undecided or soft in their support for any candidate.
Religious voters play a significant role in Iowa politics.They faithfully show up on Caucus night.
Religious voters have demonstrated in the past a distaste for candidate who engage in the bare knuckle politics Cruz/Trump have recently engaged in.
Historically polling in Iowa has been rather inaccurate. Iowa almost always produces a surprise result.
Recent polling in Iowa has been showing strong movement to Rubio. The trends in the latest polls shows movement away from Cruz to Rubio.
Rubio has gone full out of for the religious votes. His ads spend a lot of time with him talking about his religious faith. His stump speech spend a lot of time on his faith. Rubio is a good con-man. Like most people withou any core principals, his is good at selling what ever he is talking about at any one time.
Team Cruz switched from targeting Trump to going after Rubio on Friday.
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