Here's The Real Reason That Polls Always Survey Way More Democrats Than Republicans

Bill Clinton donkey

Photo: AP

One allegation that’s been levied against some of the latest polls is that they are biased in favour of Democrats. Here’s why:In many recent polls, The per cent of people interviewed who say they are Democrats has been consistently higher than the number of people who identify as Republicans. These polls include Marquette (D +8), Reuters/Ipsos (D +22), Pew Research (D +13), University of Connecticut (D +8), and many more. 

At first glance, you might say that the pollsters themselves are biased, skewed to the left. But that’s not the best way to approach it. Polling firms call a random sampling of people and don’t seek out different partisans. It wouldn’t be accurate.

If you were to conduct a poll in New York or Texas with an equal number of self-identified Democrats and Republicans, both states would be skewed, because each of those states have more members of one party than the other. 

What some polls actually do in order to represent a state is they will sample for demographic information, like gender and race. Still, not all polls do that. 

So why are more people identifying as Democrats than Republicans? It’s a tricky question. Here are some possibilities and theories to explain the disparity:

The country has more Democrats than Republicans. 
This is the conclusion if you take the polls at face value. This is to say that more Americans identify as Democrats rather than Republicans or Independents, and that’s the reason why polls have observed a skew. It’s plausible, but it’s important to acknowledge that some of these polls have been skewing very heavily to the left.

If so, it’s been a bit of a trend. In 2010 Gallup identified that 31 per cent of Americans were Democrats and 29 per cent were Republicans with 38 per cent identifying as independent. This could just be the realisation of a trend. 

Voter Registration

More Democrats are registered to vote than Republicans
Here’s an interesting idea. Essentially, many of these polls are targeted only at Registered Voters, and the Democratic party has made ground game voter registration one of their single largest efforts in the past several cycles.

It could make sense that a higher number of Democrats said that they were registered than Republicans, even if they weren’t planning on voting. This would skew the percentage higher. 

This batch of Registered Voters who are not Likely Voters could be bad for the Democratic Party overall, and if this is the source of the disparity then the polls have likely been overstating the Democrats’ chances this fall. 

While only 29 states allow voters to identify party when they register, we can find statistics confirming that Democrats have outpaced Republicans with voter registration. 

From George Mason University’s Dr. Michael McDonald, recently most of the voter registration efforts directly benefitted the Democrats and states like Iowa, New Hampshire, Nevada, North Carolina and New Mexico — states Obama won — saw double digit voter registration increases that put then-Senator Obama over the top. 

prison phone

Photo: Getty Images

There is something wrong with the way polls sampleThe polling firms use a mix of strategies to reach out to respondents. The three main strategies are Landline phones, Cell phones and Internet.

Each of these comes with their own caveats and problems. People with landline phones skew older and more conservative, people with cell phones skew younger and more liberal, and internet users skew younger and more liberal as well.

Many firms use only one of these strategies to poll, while others use a hybrid model — for instance, calling 75 per cent of respondents on landlines and 25 per cent on cell phones. One idea is that some pollsters’ cocktail of landlines and mobile phones could be disproportionate, and could be skewing the results one way or another. 

Tea Party Review

Certain Republicans self-identify as independents
While the Democratic party has stressed unity over the past few years, the Republican party has become very factional. This isn’t a bad thing, and brings voters with more disparate views to the polls for their own reasons.

However, some of the factions — the Libertarian wing, the Ron Paul wing, and the Tea Party wing, to name a few — could possibly be more inclined to identify as an Independent voter rather than with the mainstream Republican party, even if they’re going to vote Republican consistently. 

This also explains why Romney is doing really, really well with Independents.

Why is this credible? Well, according to the Winston Group, around 40 per cent of Tea Party members do not identify as Republicans, and it is somewhat doubtful that a faction formed to oppose Obama’s policies would consider supporting the Democrats. 

That’s the best we could think of to explain the gap. 

It’s a tricky problem, and there is no reason to believe that it will be settled this election. 

But it does cast doubt on some of the narratives so far in the election. Earlier, we talked about why some polls are misinterpreted because of a misunderstanding of how statistics work. If polls truly are oversampling Democrats, that’s extremely bad news for Democrats.

Even though they’re interpreted as mostly talking points, and a poll can become a partisan issue in itself, candidates rely on them for clarity and insight. If the Obama campaign is working from inaccurate numbers, it could be a career ending error. 

Now, see why almost everyone misinterprets the polling on the presidential election >

Business Insider Emails & Alerts

Site highlights each day to your inbox.

Follow Business Insider Australia on Facebook, Twitter, LinkedIn, and Instagram.