Showing posts with label Exit Polls. Show all posts
Showing posts with label Exit Polls. Show all posts

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%
Moderate30%39%6%17%9%
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.

Saturday, January 21, 2012

SC GOP Voter Demographics

UPDATE: Actual Vote % and Exit Poll % added
It seems that very few polls actually try to reach more than one (if any) demographic targets within their surveys. Monmouth is a notable exception. Unfortunately their latest poll was a week ago, before two debates, one candidate withdrawl, one candidate reentry (Cain/Colbert), a potential scandal or two, etc.. Given the number of news events just before the election and the questionable demographics of their pollees, I suspect many pollsters will be lucky if they come close to the actual vote percentage.

The 2012 SC GOP Primary (which is an OPEN primary in which Democrats or Independents can vote) should be a cross between the 1996 election where there was no Democratic primary as President Clinton ran unopposed and the 2008 SC GOP primary election where the competition was very close (however the record Democratic primary turnout drew away voters from the GOP primary). The SC population is getting older, and the GOP primary voters are getting more conservative. One counter trend is that Ron Paul is running a competitive campaign this time vs. '08 so his dedicated following dominated by younger voters (and the 50ish age group) and independent voters will somewhat offset other prevailing demographic trends. The 2000 election is another kind of anomaly in that the Democratic election was essentially unopposed and one popular candidate was very popular with independents (McCain) while the other candidate was also popular (Bush). So turnout was VERY high for the 2000 GOP primary.

When looking at polls before the election, it can be VERY important to look at the demographics of the people being polled. Many polls do not provide much information.

As a general rule, the less detail you see, or the more minimal the methods you see described to explain how one could reproduce the same result, the more likely there are to be errors in the results. In the case of this blog entry, I have omitted steps, but I will be continually revising this, to add more details, as time permits.

Many polls reported detailed demographics ONLY in the form of crosstabs so that you never see a simple statistic saying how many people over the age 65 were polled or how many people who do not consider themselves Republican were polled.

Methodoligical note: When only crosstabs are provided, I was able to estimate the range of possible values by solving many simultaneous algebraic equations and taking into account that a % without a decimal point (say 25% actually represents a number between 24.5% and 25.4999999...%) and trying both values to determine the maximum and minimum ranges of the final result. I then reduced the range, by using the maximum of ALL minimum values from each permutation of simultaneous equations. Likewise, I used the minimum of all maximum values. Perhaps if I had solved EVERY combination of simultaneous equations I could have narrowed the range a little more, but the range in most cases is reasonably narrow. Probably the midpoint is very close to the true value, but I offer no math at this point to support this notion.

The numbers for each year are either from exit polls, census data, or GOP election results. 2012 data is my best guess based on trends and my comparisons of the different mix of candidates each election.
CategoryPolitico/GWUClemsonYou Gov2012 Actual2012 Estimate200820001996
Poll: Days Before Election3-42-31-300000
Percent Undecided8%20%2%00000
Percent May Change Choice5-34%  00000
Decided Day of Election   17%19%18%9%17%
Decided Day Before or 2 Days Before Election   38%17%16%10%14%
Decided within Last Week    50%47%38%55%
Decided in January   76%75%73%  
Decided prior year   24%25%27%  
Voters or Polled600429759601,166480,000445,499565,704278,183
Voters/Adult Pop Voters   16.5%13.1%13.0%18.8%11.1%
GOP Primary Winner/%Romney 37%Gingrich 32%Gingrich 33%Gingrich 40%?? 30%McCain 33%Bush 53%Dole 45%
GOP 2nd Place/%Romney 30%Romney 26%Romney 29%Romney 28%?? 27%Huckabee 30%McCain 41%Buchanan 29%
Dem Primary Winner/% or GOP 3rd PlacePaul 11%Paul 11%Paul 18%UnopposedObama 55%Gore 92%Unopposed
Dem 2nd Place/% or GOP 4th PlaceSantorum 10%Santorum 9%Santorum 16%No OneClinton 27%
Edwards 18%
Bradley 2%No One
GOP %  71%71%65%78%61%69%
Indy %  27%25%28%18%30%26%
Dem %  2%4%7%5%9%5%
Very Conservative %  45%36%40%34%24%25%
Somewhat Conservative %  44%32%28%34%37%41%
Moderate or Liberal%  11%32%32%31%40%33%
Moderate %   23%22%24%29%25%
Somewhat Liberal %   7%7%5%8%6%
Very Liberal %   3%2%2%3%2%
Male (census data)51%49%53%51%52% (48%)51% (48%)50% (48%)53%
Age 65+ (census data)50% 29%27%26% (18%)?? (17%)25% (16%)23% (16%)
Age 60+ (census data)64%   36% (26%)35% (25%)35% (22%)32% (23%)
Age 45-64 (census data)40% 46%45%43% (35%)??% (35%)40% (31%)37% (28%)
Age 45-59 (census data)27%   33% (27%)32% (27%)30% (25%)28% (21%)
Age 30-44 (census data)8% 16%19%20% (25%)23% (26%)25% (30%)31% (32%)
Age 18-29 (census data)1% 9%9%11% (22%)10% (22%)10% (23%)8% (24%)


Category20/20 InsightMonmouthARGNBC/MaristPPP2012 Actual2012 Estimate
Poll: Days Before Election4-66-91-24-51-300
Percent Undecided4%7%2%8%5%00
Percent May Change Choice   16-45%22%00
Decided Day of Election     17%19%
Decided Day Before or 2 Days Before Election     38%17%
Decided within Last Week      50%
Decided in January     76%75%
Decided prior year     24%25%
Voters or Polled5129636006841540601,166480,000
Voters/Adult Pop Voters     16.5%13.1%
GOP Primary Winner/%Romney 34%Romney 33%Gingrich 40%Romney 34%Gingrich 37%Gingrich 40%?? 30%
GOP 2nd Place/%Gingrich 23%Gingrich 22%Romney 26%Gingrich 24%Romney 28%Romney 28%?? 27%
GOP 3rd PlaceSantorum 15%Santorum 14%Paul 18%Paul 11%Santorum 16%Santorum 17%Paul 20%
GOP 4th PlacePaul 11%Paul 12%Santorum 13%Santorum 14%Paul 14%Paul 13%Santorum 10%
GOP % 69%76%62.5-68.7%75%71%65%
Indy % 30%24%31.3-37.5%21%25%28%
Dem % 1%  4%4%7%
Very Conservative % 41%* 10.5-32.9%41%36%40%
Somewhat Conservative % 38%* 31.7-72.9%35%32%28%
Moderate or Liberal% 21%* 17.7-35.4% 25%23%32%
Moderate %     23%22%
Somewhat Liberal %     7%7%
Very Liberal %     2%3%
Male (census data) 52%52%40-50%53%51%52% (48%)
Age 66+ (census data)    32% 25% (17%)
Age 65+ (census data) 26%   27%26% (18%)
Age 45-64 (census data) 41%   45%43% (35%)
Age 46-65 (census data)    38% 44% (35%)
Age 45+ (census data) 67% 72.7-77.8%  69% (53%)
Age 18-44 (census data) 33% 22.2-27.3%  31% (47%)
Age 30-45 (census data)    22% 21% (26%)
Age 30-44 (census data)     19%20% (25%)
Age 18-29 (census data)    8%9%11% (22%)
* Before weighting due to voting history and other demographics (likely age, sex, race and perhaps party id)


CategoryWe Ask AmericaInsider AdvantageIpsos/ReuterCNN/Time2012 Actual2012 Estimate
Poll: Days Before Election238-114-800
Percent Undecided14%2%10%8%00
Percent May Change Choice   43%00
Decided Day of Election    17%19%
Decided Day Before or 2 Days Before Election    38%17%
Decided within Last Week     50%
Decided in January    76%75%
Decided prior year    24%25%
Voters or Polled988718398505601,166480,000
Voters/Adult Pop Voters    16.5%13.1%
GOP Primary Winner/%Gingrich 32%Gingrich 32%Romney 37%Romney 33%Gingrich 40%?? 30%
GOP 2nd Place/%Romney 28%Romney 29%Paul 16%Gingrich 23%Romney 28%?? 27%
GOP 3rd PlacePaul 14%Paul 15%Santorum 16%Santorum 16%Santorum 17%Paul 20%
GOP 4th PlaceSantorum 9%Santorum 11%Gingrich 12%Paul 13%Paul 13%Santorum 10%
GOP %  100%63-83%71%65%
Indy %   17-37%25%28%
Dem %    4%7%
Very Conservative %    36%40%
Somewhat Conservative %    32%28%
Moderate or Liberal%    32%32%
Moderate %    23%22%
Somewhat Liberal %    7%7%
Very Liberal %    2%3%
Male (census data)    51%52% (48%)
Age 65+ (census data)    27%26% (18%)
Age 45-64 (census data)    45%43% (35%)
Age 30-44 (census data)    19%20% (25%)
Age 18-29 (census data)    9%11% (22%)

IPSOS claims to have weighted results to "South Carolina current population registered voter data by gender, age, education, ethnicity and an eight item political values scale".

Time/CNN claims to have weighted to "reflect statewide Census figures for gender, race, age, education and region of the state." Since older people are much less likely to vote, and virtually no non-whites vote in the GOP primary, it is unclear how much this is a distortion of the actual voting population for this primary.