The Battleground States: True Vote Sensitivity Analysis

06 Nov

The Battleground States: True Vote Sensitivity Analysis

Richard Charnin
Nov.6, 2012

A forecasting model that does not utilize a Sensitivity Analysis of alternative forecast assumptions is incomplete. This analysis of 10 battleground states is based on various voter turnout and vote share scenarios.

The states are: CO FL IA NC NH NV OH PA VA WI

In 2008, Obama won the recorded vote by 52.9%-45.6%.
He won the unadjusted state exit poll weighted aggregate by 58-40.5%
The True Vote Model indicated that he won by 58.0-40.3%

In the 10 states, Obama’s…
Average 2008 recorded share: 53.3%
Average 2008 unadjusted exit poll: 57.8%

2012 True Vote Model: 54.9%
2012 Poll-based projected share: 51.6%

The following base case assumptions apply to all 10 states:
1. The number of returning voters is based on the 2008 state exit poll.
2. Voter mortality: 5% (1.25%/year)
3. Turnout: 95% of Obama 2008 voters; 97% of McCain voters.
4. Obama wins 92% of returning Obama voters and 5% of McCain.
5. Romney wins 95% of returning McCain voters and 8% of Obama.
6. Even split of new voters.

Given the above, there are two sets of sensitivity tables.
Table 1: Obama shares of returning…
Obama voters (87-97%); McCain voters (0-10%)

Table 2: 2008 turnout of…
Obama voters (92-98%); McCain voters (94-100%)

There are 9 scenario combinations in each table.
Of the total 18 scenarios, Obama won 14 in FL, 17 in OH, 15 in NC, 12 in CO, 17 in NV. He won all 18 scenarios in WI, VA, PA, IA and NH.

Example: Ohio
Table 1: Vote shares
Worst case: Obama 0% of returning McCain; 87% of returning Obama.
Obama loses by 66,000 votes.
Base Case: Obama 5% of returning McCain; 92% of returning Obama.
Obama wins by 495,000 votes.

Table 2: Voter turnout
Worst case: McCain 100%; Obama 92%.
Obama wins by 307,000 votes.
Base Case: McCain 97%; Obama 95%.
Obama wins by 445,000 votes.

Link to the Sensitivity Analysis.

The analysis indicates that Obama should do quite well in these battleground states – unless, of course, the elections are stolen.

Election Model Forecast; Post-election True Vote Model

2004 Election Model (2-party shares)
Kerry 51.8%, 337 EV (snapshot)
State exit poll aggregate: 51.7%, 337 EV
Recorded Vote: 48.3%, 255 EV
True Vote Model: 53.6%, 364 EV

2008 Election Model
Obama 53.1%, 365.3 EV (simulation mean);
Recorded: 52.9%, 365 EV
State exit poll aggregate: 58.0%, 420 EV
True Vote Model: 58.0%, 420 EV

2012 Election Model
Obama Projected: 51.6% (2-party), 332 EV snapshot; 320.7 expected; 321.6 mean
Adjusted National Exit Poll (recorded): 51.0-47.2%, 332 EV
True Vote Model 56.1%, 391 EV (snapshot); 385 EV (expected)
Unadjusted State Exit Polls: not released
Unadjusted National Exit Poll: not released

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Posted by on November 6, 2012 in 2012 Election


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