When NASA or the DoD need to track a satellite we use multiple parallel models to account for gravity, solar pressure, the height and drag of the atmosphere (what little there is at orbital altitudes) and a variety of other models. We update the measurements in all these factors and run statistical models, weighting newer data over older data, all the while checking for the random outlier measurement. Even with all this we can only predict solid orbits for about 7 days before we have to update them in many cases.

And that is with a well characterized and physics bases system to model. Oh if opinion polls could be so simple!

Being a bit of a math addict I sometimes forget that pollsters are not really as versed in scientific sampling as some engineers and scientists, though the case could be made they are better than the scientists who modeled ‘global warming’ and CO2 levels. I found two commentaries very interesting and revealing.

One is from Jay Cost at RCP which illustrates why the polls are a problem, but interestingly Jay cannot find the answer to the conundrum:

On Friday, I noted that the differences among the national polls is large enough to suspect that something other than random variation is causing the disagreements.

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It is unlikely that random variation would produce these effects. Today’s Rasmussen poll shows McCain significantly higher than the RCP average, and it has consistently been higher than the RCP average for the last three weeks. IBD/TIPP frequently pegs Obama’s number significantly lower than the RCP average, and it has shown him lower than the RCP average every day since it began. The GWU/Battleground poll has shown McCain consistently higher than the RCP average for 10 of the last 10 release dates, frequently at significant levels.

As I noted in my posts on the Bi-Poller world of polls (here and here) if one groups polls by how they treat party affiliation in their final results into two categories we find two distinct families of polls with consistent results. Either pollster use the historical party turnout models which would give Democrats a maximum advantage of 4% over the GOP side (‘traditional’ polls to steal the Gallup vernacular), or pollster assume Democrats will experience a never seen in modern times advantage of 8-12% in voter turnout (the ‘extended’ polls).

Once you realize we have to opposing views on turnout expectations the polls are quite consistent within their respective group – and the RCP ‘average’ falls between the two groups (showing either higher or lower expectations for Obama and the Dems). Both assumption cannot be true – one model will be proven right next week, and the odds are stacked against the ‘extended’ turnout models. In fact, if the pollsters and analysts were being honest, they would not that the only way for Obama to achieve the lead he has now is for a never before seen advantage in voter turnout for the dems – a historic wave that would break the pattern going back decades.

The other commentary that caught my eye was from the left, and the fact many democrats are subconsciously or intuitively seeing the problem for Obama:

With all due respect to Judis, I’m not popping anything just yet, except maybe some sleeping pills to get me through the night. (That’s for you, John.) In the last few days, pretty much every tracking poll I trust (WaPo, Gallup, Rasmussen) and several I either don’t trust (that would be you, Zogby) or don’t have much of an opinion about (Kos,Investor’s Business Daily) has shifted toward McCain, in some cases sharply. While some of the more traditional (i.e., non-tracking) polls show Obama with a big lead–like the Pew poll Judis cites–these polls tend to reflect older information.

As I noted earlier, Pew is far from ‘traditional’ in their turnout model.  They are assuming some of the highest disparity in turnout models for the Dems amongst all the ‘extended’ polls. But the author sees the danger:

As of this writing, Obama’s lead in the national tracking polls looks to be around five points (I get 5.5 when I average all six of the trackers I mentioned, along with theHotline and Battleground trackers, which haven’t changed much in the last few days). If that drops two-to-three points, as it easily could in a week, I don’t think it’s crazy to think McCain will have a shot at winning Pennsylvania, Virginia, and/or Colorado. 

If it drops to a tie in these ‘traditional’ polls (though Rassmussen took himself out of this category by using his sample results to set his weighting – a big time statistical no-no) then Obama has little chance of winning. And right now my estimate is the ‘traditional’ polls are now at Obama +4% and falling.

Averaging these two classes of polls is a fool’s errand. Either McCain-Palin get out the vote and limit their disadvantage to 2-4% in turnout, there is some mythical wave of Democrat love out there. It is remotely possible the latter is true, but the odds are incredibly low given the historic peaks for great democrat years. As of tonight the irrationally optimistic national number for Obama is +9.2%, and the historically proven model is showing +4%. Only one number is closing in on what the result will be Tuesday – the other one is simply flat out wrong. It is either-or, not an average. People can decide which model they like or believe, but the math says it is one or the other.

 

 

Given the tightness of the last two presidential elections and the trend for races to tighten in the last week and tip to the conservative side, I would say it is not surprising Obama and McCain are spending their final days in PA and VA.

Update: I forgot to link to the latest from Obi-wan Kenobi:

That’s why key Obama people are nervous. People like Ed Rendell ought to feel good about Pennsylvania. He doesn’t. He knows it can slip away. And don’t forget Obama lost primaries where he had an eight point lead.

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What is justified is hope. A stable week economically and a little bit of a finish by McCain and it is doable. Remember this isn’t 1974 or even 1976 in one important way. There’s a GOP candidate who probably had  blow- out debate . And that may be  the single most important  thing voters most remember on election day.

With falling gas and energy prices, a recovering stock market (fingers crossed there) and home values rebounding here and there it could be just what the doctor ordered. And then there is the image of Obama playing Robin Hood with our hard earned money ….

Tags: 2008 Election, Polls, Traditional. Extended