Those who follow the polls may be wondering how to make sense of all the information they contain. That's especially true for the "horse race" -- the polling question that asks participants which candidate they would vote for if the election were held today.
Right after the Republican Convention, polls released within days of one another ranged from a double-digit lead for President Bush to a tied race. CBS News' most recent poll had Mr. Bush leading John Kerry by eight percentage points among registered voters (with likely voters not much different).
Why are these polls, conducted by reputable pollsters with many years experience in the polling business, showing such different results? There are a number of reasons why the polls differ.
For example, a survey conducted by the Pew Research Center for the People and the Press (which regularly polls on current events, politics and the media) first asks respondents how much attention they have been paying to a number of recent news topics before asking whether people are registered or how they will vote. While in theory this should not affect how people vote, it may focus attention on certain issues – and mentioning Iraq, the economy, and the ad campaign by the "Swift Boat Veterans for Truth" can affect the responses of less committed voters.
Some organizations ask only one question. On the other hand, The Gallup Organization uses a series of questions that were first developed to be used in the last weeks of a campaign. Applying that series for the entire year before the election may have some unintended consequences and as we've seen, the Gallup Polls of likely voters have shown greater swings than many other polls.
Additionally, some polling organizations limit the number of voters included in their "likely voter" group, not letting the number exceed their expectations for what turnout will be. That can exclude some voters who would fit another polling organization's definition of likely voters.
In fact, right now the polls are fairly consistent. Taking a look at the most recent major pre-election polls among registered voters shows similar results. All of these polls – at least for now -- report a lead for Mr. Bush over John Kerry.
RECENT POLLS (among registered voters)
For example, the latest NBC/Wall Street Journal poll shows Mr. Bush with a 3-point lead over Kerry. The latest CBS News poll gives the President an 8-point lead. Why are they different?
The dates over which the two polls were conducted are fairly close. Numbers from both polls are among registered voters. But the NBC/Wall Street Journal Poll asks quite a few questions that CBS News does not ask before asking respondents for whom they would vote.
CBS News asks respondents whether they are registered to vote, how likely they are to vote in November, and how much attention they are paying to the election before asking the vote question.
The NBC/Wall Street Journal Poll asks registered to vote, interest in the elections, whether the country is headed in the right direction, approval of the job Mr. Bush is doing (as president, handling the economy, handling foreign policy and dealing with terrorism) and whether Mr. Bush deserves to be re-elected before asking for whom they would vote.
Each organization has its reasons for structuring questionnaires as it does. Nevertheless, differences in question order could well account for disparities in the horse race results.