Political Polling: Art Behind the Numbers

Everyone has read about the results of political polls. As we near any major election, the media breathlessly reports on the ups and downs of various candidates. And because they get so much attention, partisans from across the political spectrum love to attack polls. They point out where a poll may be lacking if their candidate of choice doesn’t look like the winner. Or they spin why the person who dominates the poll may have secret weaknesses that the survey did not capture.

Political polling is a type of public opinion polling.
When done right, public opinion polling is an accurate social science with strict rules about sample size, random selection of participants and margins of error. However, even the best public opinion poll is only a snapshot of public opinion at the particular moment in time, not an eternal truth [source: Zukin]. If you poll public opinion on nuclear energy right after a nuclear disaster, it's going to be much lower than the day before the disaster. The same is true for political polls. Voter opinion shifts dramatically from week to week, even day to day, as candidates battle it out on the campaign field.

Getting a Representative Sample

The mission of political polling is to gauge the political opinion of the entire nation by asking only a small sample of likely voters. For this to work, pollsters have to ensure that the sample group accurately represents the larger population. If 50 percent of voters are female, then 50 percent of the sample group needs to be female. The same applies to characteristics like age, race and geographic location. To get the most accurate representative sample, political pollsters take a page from probability theory [source: Zukin]. The goal of probability theory is to make mathematical sense out of seemingly random data. By creating a mathematical model for the data, researchers can accurately predict the probability of future outcomes. Political pollsters are trying to come up with models that accurately predict the outcome of elections. To do that, they need to start with a perfectly random sample and then adjust the sample so that it closely matches the characteristics of the entire population.