[Fipherion]

The pollers know what they're doing. Theres a lot of statistical theory around the idea of polling and I'm sure they don't just walk up to a group of people and say ask them questions. If you pick a fairly random sample is usually safe to say that their opinion is representative of the whole to within a margin of error that is calculated on various factors about the data.

The +-2% error they claim is some sort of confidence interval where you they can say with a certain amount of confidence that the REAL number is within that range. I don't know what level of confidence they usually use but its probably somewhere in the 80-95% confidence range. No matter what, there is always the chance that the actual value will be outside the range. Even with 95% confidence, 5% is not 0% so theres a fairly reasonable chance for your conclusions to be wrong. When that happens, it doesn't mean you should throw out all your faith in statistical data. It just means you didn't get a very representative sample.

In the end, its always good to question the pollers data but they're going to get it right more than they get it wrong.