With every new presidential election it seems the number of pollster keep growing. Every day there are countless polls analyzing voting trends by race, age, sex, religion, geographic location. This polling conducts research on just about every variable you could possibly imagine.

But how are these polls taken, and who are these pollsters talking to? With the presidential race coming down to the wire, the science of polling and that all so constant margin of error begs to ask the all-important question: Just how accurate ARE they?

Political polling is public opinion polling. When done correctly, 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. Voter opinion shifts dramatically from week to week, even day to day, as candidates battle it out on the campaign field.

Political polling wasn't always so scientific. In the late 19th and early 20th centuries, journalists would conduct informal straw polls of average citizens to gauge public opinion on politicians and upcoming elections. A newspaperman traveling on a train might ask the same question to everyone sitting in his car, tally the results and publish them as fact in the next day's paper.

Today, the top political polling organizations employ mathematical methods and computer analysis to collect responses from the best representative sample of the American voting public. But there's still plenty of "art" in the science of political polling. Even random responses must be adjusted and sifted to identify subtle trends in voter opinion that can help predict the eventual winner on Election Day.