In the 2020 election, all 21 of the final national polls showed Biden ahead — and he was ahead. He won by 7 million votes. Moreover, the average of the final polls came close to nailing Biden’s vote share: 51.5% in the polls versus 51.3% in the actual vote count.
Legitimate pollsters make money by being right. That’s why deliberate bias is rare and mistakes are feared, especially in polls taken right before elections. But even pollsters with good reputations can make faulty assumptions and unwittingly allow partisan bias to skew questionnaires, sampling, and analysis. When discussing the accuracy of polls, let’s remember, too, that prognostications made by pundits, data modelers, and betting markets are not polls, even if they’re based in part on polls.
It is important to keep in mind that polls don’t predict. They’re snapshots in time, not crystal balls. Whatever happens after the final poll is conducted won’t be measured. That’s why some polls don’t catch late-breaking shifts, a problem in the 2016 presidential election, and seem wrong when, in fact, they’re not.
Each polling method, whether door-to-door, via cellphone calls, or some combination, has strengths and weaknesses. It is essential that pollsters carefully drive quality control throughout the entire survey process. Most do, but some don’t. Cutting corners saves money, but it produces bad numbers. That’s why when polls conflict with one another, we don’t always know which ones are painting the true picture.
But one thing we do know: When reading election polls, never put too much stock in any one survey. Look at multiple polls for confirmation and always try to find the trends. Also, delve into the internal numbers not reported by the media to see whether this data support the horse race numbers. Despite limitations and margins of error, polls remain the best available measurement tool of public opinion. If they weren’t, there wouldn’t be so many of them.
Or now a marketing tool to promote predetermined people and issues as more popular then they are. Like the media, such behavior destroys credibility for all polls.
My pliers are the best tool I have for hammering nails since I lost my hammer, but that doesn't mean I should use the pliers as if they get the job done. They won't.