The Democratic Swing & Independent Swing--What The SUSA Polls Can Tell Us

by: Paul Rosenberg

Sat Jun 07, 2008 at 16:12


[Updated Below]

On Thursday, Chris wrote a diary, "Democrats More Important Than Independents in 2008", in which he argued:

From 2004 to 2006, Democrats actually made more gains among self-identified Democrats than they made among self-identified Independents. Now, in 2008, because partisan self-identification has shifted starkly in favor of Democrats, Barack Obama has much more to gain for self-identified Democrats than he has from self-identified Republicans and Independents combined.

For the past four months, according to Rasmussen, the average national partisan self-identification has been Democrats 41.4%, Republicans 31.7%, and Independents / Others at 26.8%. Even when Rounding in favor of Republicans, if the general election electorate identified 41% Democratic, 32% Republican, and 27% Independent, and if Obama held down 90% of Democrats while McCain held down 90% of Republicans, then Obama would only need 37% of Independents to reach 50% +1. To put this in perspective, in 1984 Walter Mondale received 36% of the Independent vote, 1% shy of what Barack Obama would need.

If Democrats make up 41% of the electorate in November, and Independents only make up 27%, then Obama has significantly more potential votes to gain among self-identified Democrats than he has to gain among self-identified Independents. Let's say that Obama's possible range of support among self-identified Democrats is 75% to 90%. This would represent 6.2% of the electorate. By contrast, let's say that Obama's possible range of support among Independents 40% to 60%, representing 5.4% of the electorate. As such, according to these estimates, which probably exaggerate the possible Independent range, Democrats are actually a bigger swing block than Independents.

In this diary, I want to use the recent Survey USA polls testing possible VP nominees for the purpose of taking a closer look at Chris's argument here, particularly the last sentence, saying that Democrats are a larger swing block than indendents.  As we'll see on the flip, of the 15 states analyzed, this is clearly true of all but one state....

Paul Rosenberg :: The Democratic Swing & Independent Swing--What The SUSA Polls Can Tell Us
Methodology

First let me explain the methodoloy used.  The different combinations of VP candidates produced very large ranges of potential support.  For instance, in Virginia, this ranged from Obama winning by 18 with Edwards as his running mate against McCain/Pawlenty, to losing by 6 points with Sebelius as his running mate against McCain/Lieberma, a swing of 24 points:

In addition to these topline results, SUSA released cross-tabs, allowing us to analyze the swing among Democrats and Independents as well.  So we will use these swings as pretty good proxies for the amount of voters in play in each of these categories-at least at this time-and see what they tell us.

All Voters

We beging with a somewhat busy chart, that has the advantage of making it clear how we're proceeding-we will simplify the picture, once I've explained where things are coming from.  The chart has two heavy lines, showing how the two candidates did in each state, in head-head competition with no VPs, and four lighter lines showing their highest and lowest totals of all the VP matchups listed.  It's organized in ascending order of Obama's head-to-head vote:

Now, for our purposes, we're not really interested in the straight-up head-to-head results, so we just drop those lines out and get a simpler picture:

Next, we simplify further by shifting from ranges of votes to the swing between the high and low end of the ranges.  This reduces each state from four data points to two.  But then we add a new data point-the average of the two swings.  That's because the swings are not symmetrical, due to people who don't choose either candidate.  This new data point is actually half of the total swing, since the total swing is the sum of the swings for both parties.  But taking the average leaves everything on a similar scale, so that's the figure I've chosen to use:

This chart is the simplest overall summary of just how many voters are in play, percentage-wise, in each of the states.  

Now it's time to take a similar look at the independents and Democrats.  But since we've been through this whole process once, we don't really need to do it again.  We can go striaght to the final graph, that has the most information in the simplest-to-grasp form.

Indepedents and Democrats Compared

Independents clearly have a very wide degree of variation in support (swing), as we would normally expect.  Indeed, the variation itself varies considerably from a low of just under 10% to a high of over 50% (remember the chart shows the average swing of the two candidates, we have to double it to get the total swing.)

In contrast, the Democrats show generally lower levels of swing, and less variation in these levels, from about 18% to about 28%:

However, as Chris noted, Democratic party membership is up.  And SUSA provides voter registration figures that allow us to weight the totals from the above charts.  We can then take the weighted figures and combine them with figures for all voters for each state, and come up with the following chart, that clearly shows the vartiation in Democratic support dominates over the variation among independents:

Finally, here is the data from the last chart, in table form, with the addition of columns that show how large the Democratic and independent swings are as a percentage of the over-all swing:

Swing Range Based on VPs
  Amount of SwingPercent of Swing*
StateTotalDemsIndsDiffDemsIndsDiff
WA18.0%7.3%6.0%1.3%40.6%33.2%7.4%
CA19.0%10.6%5.0%5.6%55.6%26.3%29.3%
OR19.0%9.6%5.9%3.7%50.5%31.0%19.5%
OH20.0%12.0%6.8%5.1%59.8%34.2%25.6%
WI20.0%7.9%7.5%0.4%39.6%37.7%1.9%
MA21.0%12.2%10.1%2.0%57.9%48.3%9.6%
NY21.0%13.8%5.8%8.0%65.5%27.5%38.0%
NE21.0%8.7%3.2%5.5%41.6%15.4%26.2%
PA22.0%10.5%4.1%6.4%47.5%18.6%28.9%
MN23.0%9.8%6.6%3.2%42.8%28.7%14.1%
MO24.0%11.9%6.4%5.4%49.5%26.8%22.7%
KS24.0%10.8%3.8%7.1%45.0%15.6%29.4%
VA26.0%10.3%8.6%1.7%39.4%33.0%6.4%
NM27.0%14.0%2.6%11.4%52.0%9.8%42.2%
IA34.0%12.6%13.2%-0.6%37.1%38.8%-1.8%
Avg22.6%10.8%6.4%4.4%48.3%28.3%20.0%
* Swings are not strictly additive, as they represent maximums from a range of values, but can safely be directly compared.

Thus, we see that on average, the Democratic swing of 10.8% is almost half of the total swing, and is 4.4% higher than the independent swing of 6.4%.  That is truly a much more important group of voters, numerically.  But, of course, another way to look at it is that Democrats are, as usually, a cantankerous lot, and there's a lot of room to go to bring them all together.  The good news, however, is that now that they are a much larger group than the Republicans, or the independents, there's a much bigger payoff for bringning them together.


[Update]: It seems pertinent to note that the Rasmussen Daily Tracking Poll has Obama with 80% of the Democratic vote against McCain for the first time since the polling began:

The Rasmussen Reports daily Presidential Tracking Poll for Saturday shows Barack Obama attracting 46% of the vote while John McCain earns 42%. When "leaners" are included, Obama now leads 48% to 45%. Leaners are survey respondents who initially do not favor either candidate but indicate their support on a follow-up question. One week ago today, McCain had the edge over Obama, 46% to 43%....

Obama's bounce is primarily the result of Democrats beginning to unify behind his candidacy. For the first time all year, Obama is supported by 80% of Democrats over McCain. In recent months, his support from Democrats has typically been in the high-60's or low-70's range.

I hope the analysis above gives you a greater sense of satisfaction in hearing this news.


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I never had a doubt! (4.00 / 1)
Obama's bounce is primarily the result of Democrats beginning to unify behind his candidacy. For the first time all year, Obama is supported by 80% of Democrats over McCain.
 

We all know what's in our self-interest, and we all know there's nowhere else to go.  I think this is going to be a rout.  The Dems are going to take over in numbers equal to or greater than what the Republicans had in the Bush hay day.  

Great job explaining the charts.  They would seem to support a "strong" victory for Dems. I hope somebody can persuade Edwards and Obama to run as a team.  I would like it, and the numbers really work.  


I hope (0.00 / 0)
SurveyUSA does these polls again including Clinton as a VP choice. Those results would be pretty illuminating.  

Well They Included Her In One Poll (0.00 / 0)
They did the Michigan poll completely differently, pitting a larger number of Dem VPs vs. Romney as the sole GOP VP.  Clinton, Gore and Edwards were virtually tied, with everyone else further back.

Beats the hell out of me why they used such a poor selection of candidates on the Dem side.  Rendell?  WTF?  Hagel or Sebelius, I guess I could see one or the other. But both?  I would have thought Clinton, Edwards, Richardson, maybe Dodd or Feingold.

Go figure.

"You know what they say -- those of us who fail history... doomed to repeat it in summer school." -- Buffy The Vampire Slayer, Season 6, Episode 3


[ Parent ]
Possible November projection (0.00 / 0)
A few weeks ago Markos at Daily Kos discussed the difference in polling for Democratic senatorial candidates in the 2006 election between May and November. Putting the numbers together I calculated that the Democratic candidates had gained an average 6 percentage points in that time period. Does anyone know of comparable measures of polling between May/June and November?

With Obama now polling 48 to 45 percent over McCain, if the above extrapolation holds this year, we may be looking at an election in the 54 percent Obama to 46 percent McCain range in November.

And it may be a bigger win than that (barring residual racism). In 2006 the overall national vote for Democratic congressional candidates was just shy of 55 percent--about what the above extrapolation holds for Obama. Of course, since 2006 Democratic Party identification, primary turnout, and enthusiasm have all increased.

Indeed, if we can expect a Democratic Party victory in the presidential and congressional races of around 55 percent, then we may be looking at a congressional election similar to that in 2006, or about 30 new Democratic seats in the House and six or more in the Senate--that is, close to a realigning election.

These are just extrapolations, but with some basis in recent history. Maybe Chris can make some calculations that take in more kinds of data.    


A Realigning Election, Yes. (0.00 / 0)
That's just the point.  We shouldn't be fired up about winning.  Winning won't be enough.  We saw that in 2006.  We need to crush the GOP, and leave the media speechless.

That's what we need to do.

"You know what they say -- those of us who fail history... doomed to repeat it in summer school." -- Buffy The Vampire Slayer, Season 6, Episode 3


[ Parent ]
Leave the media speechless? (0.00 / 0)
That's a nice fantasy you've got there...

I support John McCain because children are too healthy anyway.

[ Parent ]
I'll Settle For Babbling Incoherently, Then... (0.00 / 0)
Oh, wait... they already do that.

"You know what they say -- those of us who fail history... doomed to repeat it in summer school." -- Buffy The Vampire Slayer, Season 6, Episode 3

[ Parent ]
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