In the mysterious world of opinion polls, all is not what it seems

What do polls have in common with James Joyce and baseball scores? They're Greek to most people – until they learn how to read them.

Polls are like baseball box scores and the works of James Joyce. You can learn more if you know how to read them.

Surprised? Maybe you thought pollsters just made their stuff up – you know, by throwing darts at a board (“Bulls eye! White House job approval up 10!”) or consulting their astrologer.

Maybe some do. But most pollsters are serious quantification professionals. They look at poll numbers and see things amateurs don’t.

Take one of the most basic of political measures: the generic congressional ballot. It’s based on this question: “If elections were held today, which party’s candidate would you vote for?”

Right now, that poll, on its face, doesn’t show a clear winner. Forty-six percent of registered voters say they would vote Republican, and 45 percent say they would favor Democrats, according to a Gallup poll released May 16.

Wow, that means the fall elections will be close, right? Not necessarily.

For one thing, there are more Democrats in America than Republicans. As a Gallup analysis notes, it is thus rare for the GOP to ever lead the registered-voter generic congres­sional ballot.

“This was the case even when Republicans were the majority congressional party from the mid-1990s to the mid-2000s,” notes a Gallup guide to understanding key election indicators.

For another thing, a larger percentage of the GOP’s registered voters actually vote. This is how Republicans remain competitive on the congressional level, despite Democratic Party superiority in numbers.

What does all this mean? It means that on this particular measure, if Democrats and Republicans are tied, the Republicans are actually ahead by about five percentage points.

To overcome the hidden GOP advantage, Democrats must be ahead by double digits in the general congressional ballot to have any assurance of prevailing in the fall.

Remember, there are still six months until Election Day, and a lot can happen between now and then, so this discussion is more of an illustration than a prediction of what will happen in the fall.

What’s Decoder’s personal prediction of November’s congressional vote? We’ll get back to you. Our astrologer has yet to return our call.


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Robert Gibbs: Democratic voters’ lack of enthusiasm puzzling

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