How accurate are Political Polls?

There seems to be fresh polling data on the presidential election every day leading up to November 2024. From head-to-head contests between President Joe Biden and former President Donald Trump to bouts with the probable GOP candidates, these polls portray a range of possibilities.

Even though Biden is now leading Trump in some national polls, this is not always the case; for example, recent polling in Pennsylvania showed that Biden was much ahead of Trump in that state. With all the current debate around these numbers, however, one must wonder: just how reliable are political polls?

The results of polls may be wildly inaccurate, as has been shown in recent years. As an example, HuffPost’s election day 2016 polling found that Clinton had a 98% probability of defeating Trump. Even though the polls were drastically off that year, for the 2020 election, the vast majority of polls properly indicated that Biden would beat Trump. Given the pros and cons of polling accuracy, how much faith should the public have in polls?

How do people vote in political polls?
There is a need for surveys “because asking each individual in a community would be expensive and logistically difficult,” as stated in a CalTech paper. But “a sample size of just 1,000 to 1,500 people can be enough to estimate national opinion in the United States with a high level of accuracy.”

Pollsters “draw a random sample of participants from computer-generated lists of landline and cell phone numbers (increasingly, polls are also being conducted online),” according to CalTech, who stated that random sampling is a standard technique in polling. It “gives everyone in the population an equal chance of being included or not.”

While “different polling organizations conduct their surveys in quite different ways,” according to a 2020 analysis by the Pew Research Center. According to Pew, although CNN and Fox News used phone surveys, Politico, The Associated Press, and CBS News used a variety of internet methods.

Can we trust these surveys?
The Electoral College has taken a lot of heat recently, especially during the most recent presidential elections. Politically, “national surveys of the 2020 presidential contest were the least accurate in 40 years,” even though the majority of polls accurately projected Biden’s win in 2020.

Is the reliability of polls so compromised? Not always, but they may provide an inaccurate image. The reason is, that the real margin of error is often about double the one reported,” according to Pew. A margin of error of less than 3% is common in most polls, which “leads people to think that polls are more precise than they are,” the site said. However, this tolerance “addresses only one source of potential error: the fact that random samples are likely to differ a little from the population just by chance.”

According to Pew, three other distinct causes of data inaccuracies may occur during polling; however, the margins of error for most surveys do not account for these measures. “Consequences for data quality, as well as accuracy in elections,” Pew stated, referring to the varying methods of surveying. Consequently, The New York Times found in 2016 that most historical surveys had a margin of error closer to 6% or 7%, rather than 3%. The Times said that this ranges from 12 to 14 data points of inaccuracy.

However, surveys are still sometimes accurate and provide a good sense of how the American people feel. The 2022 midterm elections’ polling was “historically accurate,” according to FiveThirtyEight. A contributing factor to this is the fact that pollsters started “increasingly weighting surveys based on whom respondents recall voting for in a previous election, in addition to adjusting for standard demographics such as race and age,” as reported by the Times.

While this technique has been around for a while and is used to determine polls in other nations, it is just now becoming popular in the US. It was also discovered after the 2016 election that pollsters failed to adequately represent voters with lower levels of education, thus distorting the results. Following this, pollsters “adopted education as an additional survey weight, and a cycle of accurate polls in 2018 seemed to reflect a return to normalcy,” the Times noted.

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