Tuesday, January 24, 2012

Solid Demographics + Most Recent Poll = Best Prediction

Reviewing the SC primary results, the poll closest to the actual voting date that had good demographics was the most accurate. That poll was PPP.

Virtually every primary has at least 10% of the vote being decided on the day of the election. Voters who decided on the day of the election or within a few days make up at least 20% and in SC it was a whopping 55%!

So trying to predict a vote within a couple percentage points, which is important when you have 4 to 7 viable contestants, seems to require some sort of mysticism to be accurate.

But if you simply poll in those last few days, and model your demographics based on past demographics, taking into account any obvious reasons for a significant change from the most recent election or two (e.g. voters can reasonably easily switch from one primary/caucus to another... even in a so-called "closed" primary, or a prior contest was moot because the party's nominee was clear by the time that prior year's contest was held, etc.

Anyway, looking at the just released PPP poll for Florida and reviewing the exit poll data, I see no reason to consider any major change in demographics from the 2008 exit poll and for the most part, the PPP poll deviates very little from that.

But here is one outlier: it says 40% of voters describe their political philosophy as 40%. That is WAY off the mark. In 2008 it was 27%. In 2000 and 1996 the Florida primary was preceeded by two dozen contests, so voter interest is low. How that affects political philosophy is not yet clear to me. However, the very conservative % in those two contests was even lower at 20% and 21%. Even though Florida is a state with higher growth than most other states, a demographic shift statewide seems virtually impossible.

So how would this affect the results?
Let us assume that the conditional probabilities crosstab reported by PPP is not significantly affected by any other demographic anomalies (one I noted was the much lower hispanic sample of 7% vs. 12% in the '08 primary).

So the conditional probability of choosing a candidate based on your political philosophy is:
Political PhilosophyNewtRomneySantorumPaulOther
Very Liberal42%34%9%5%10%
Somewhat Liberal44%23%9%20%5%
Somewhat Conservative35%42%9%9%6%
Very Conservative44%23%20%8%5%
If one assumes the exit polling in the 2008 primary is reflective of the 2012 exit polling, then the % of voters for each political philosophy is 2% very liberal, 8% somewhat liberal, 28% moderate, 34% somewhat conservative, and 27% very conservative.

For Newt Gingrich, 2%x42% + 8%x44% + 28%x30% etc... you get 36.5%.
The numbers for Mitt Romney calculate to 33.9% which cuts the 5 pt lead from Newt in half.
The numbers for Santorum and Ron Paul reverse their positions from a 3 pt lead for Santorum to a .7 pt lead for Ron Paul.

Now consider what the media narrative is when the pollsters say someone is leading by 2.5 % vs. the 8% lead reported by Insider Advantage (who gives ZERO demographics, ZERO polling methodology).

The best scientific research is open and relatively easily reviewable by anyone with the time and inclination to do so. Mistakes are found, and corrected. This is in stark contrast with the majority of media polls put out every week during election season.

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