Politics: Everything you need to know about election polls in 2020

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© Patrick Semansky/AP Photo Democratic nominee and former Vice President Joe Biden currently holds a ten point lead in national polls over President Donald Trump. Patrick Semansky/AP Photo

• With less than two weeks until Election Day, Democratic nominee Joe Biden has about a 10 percentage point lead over President Donald Trump in an average of national polls.
• National polling in 2016 was about as accurate as any presidential election since 1968, even if Trump's upset victory shocked millions of Americans.
• Business Insider answered some of the most common polling-related questions for the 2020 election.
• Visit Business Insider's homepage for more stories.

After a hotly contested presidential race in November 2016 that shocked the nation, people from around the globe are clamoring for a glimpse of what may happen in 2020.

The week in polls: Trump gains in 9 of 12 swing states, but Biden still leads in 10 of them

With just eight days to go to Election Day, both national polls and swing state surveys make it clear the race between Trump and Biden is tightening.President Donald Trump gained on his Democratic challenger Joe Biden in national polling averages, and in nine of 12 contested states. But Biden still holds a sizable lead in the national polls and is still ahead of Trump in 10 of the 12 states that could decide the election.

It's easy to get confused by political polls and surveys due to their intricacies, averages, and varying methodologies, so Business Insider answered some of the most common polling-related questions of the 2020 election:

What do the polls say?

In the race for president, Biden is currently leading Trump by about 10 percentage points in an average of national polls from FiveThirtyEight. Decision Desk HQ, an election forecasting company, predicts that Biden has an 86.7% chance of winning the election.

If Biden wins in November, it will likely be because of his robust leads in a handful of critical swing states, which include Pennsylvania — a state that Trump won in 2016 by less than one percentage point and holds 20 electoral votes. Biden leads Trump by an average of 6.2 points in state polls, according to FiveThirtyEight, and DDHQ predicts Biden has a 74% chance of winning the Keystone State given that lead.

How polling works and how it’s changed since 2016

Polls, at their best, give us a rough estimate of a candidate’s support at a given point in time. They cannot predict whether a lead is truly safe or certain. (Here are The Post’s most recent polls.) Here’s what to know about what polls can tell us, where they can fall short and what’s changed since 2016. How polls work — and what happened in 2016 U.S. presidential elections are decided by a handful of key states, and polls that cover the whole country or individual states have limits to how precise they can be. All polls have random sampling error, inherent in relying on a sample of the population.

While he still leads in many swing states, Biden's edge in Florida, a key swing state, is razor sharp. Florida possesses 29 electoral votes — the second most of any state — and was won by Trump in 2016 by just 1.2 percentage points, or nearly 113,000 votes. In an average of Florida polls, Biden currently leads Trump by 3.3 points and DDHQ suggests he has a 62.7% chance of winning in the Sunshine State.

Could the polls be wrong?

Yes. There is a very good chance that the polls are "wrong" and will not have precisely predicted the final election results. The biggest question on election night will be just "how wrong" the polls were.

Incorrect polling is one of the most common critiques of the 2016 presidential election, but in truth, the polls were not off by much. Trump, for example, outperformed the national polls in 2016 by only about 2 percentage points. In fact, the polls were about as accurate as they've been in any presidential election since 1968, according to Nate Silver, founder of FiveThirtyEight.

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While the polls were slightly off in 2016, the effects were magnified as Democratic nominee Hillary Clinton's lead in swing states was incredibly slim. Just a day before Election Day, Clinton and Trump were in a deadlock in North Carolina and Florida. As November 3 approaches, Biden currently holds close to three and four-point leads in those states and is in a better position than Clinton was.

According to polling, which states are closest?

According to FiveThirtyEight, the nine closest races are in Georgia, Iowa, Ohio, Texas, North Carolina, Arizona, Florida, Pennsylvania, and Wisconsin. Of these, Biden is currently leading in all but Ohio and Texas.

With less than two weeks until Election Day, polling in swing states are as follows:

• An average of recent polls in Texas estimate that Trump is leading in the Lone Star State by just 0.5 percentage points. If Biden can flip Texas Democratic for the first time since 1976, he is all but guaranteed an electoral college victory.
• Biden is ahead in the polls by an average of 3 points in North Carolina, a state that Trump desperately needs to bolster his chances of reelection. A large proportion of the results in North Carolina will be known on the night of the election, as the state is on the east coast, whose voting centers are among the first to close. Additionally, absentee ballots in North Carolina are validated before Election Day which allows them to be counted more quickly.
• Ohio continues to be a difficult state for Democrats to win over post-Obama, and Trump is currently leading in the state by an average of 1 percentage point in the polls, though RealClearPolitics estimates his lead may be as low as 0.6 points.
• In Georgia, Biden currently leads in the polls by about 1-1.2 percentage points, according to both FiveThirtyEight and RealClearPolitics. The state has not voted for a Democratic nominee since President Bill Clinton in 1992.
• Iowa is polling similarly to Georgia and an average of polls estimates Biden in the lead by up to 1.2 percentage points over Trump in the Hawkeye State. Trump previously beat Clinton in the state by 9.5 percentage points in 2016.
• Biden is currently leading in Arizona by an average of about 3.5 percentage points in the polls. Trump won the state in 2016 by 3.5 points — the same margin he currently trails by.
• Trump currently trails Biden by an average of 3.3 percentage points in Florida, but the race may be even closer as RealClearPolitics estimates Biden up by just 1.5 percentage points.
• In Pennsylvania, Biden leads Trump by an average of 6.2 percentage points in a state that Trump won by just 44,292 votes in 2016. The state is a must-win for Biden.
• Lastly, Biden holds an average lead of 6.6 percentage points in the polls in Wisconsin, according to FiveThirtyEight. Trump won the state in 2016 by less than one percentage point of the final vote.

To win the election, a candidate must receive at least 270 electoral votes. The tipping-point state is the state which would provide the winner with the 270th electoral vote needed to win the election and is based on the victor's margin of victory.

Fact check: Mail-in ballots arriving after Election Day will count in some states

A viral post on Facebook claims any ballot received after Election Day will not be counted. That's partly false, many states have extensions in place.A recent viral post on Facebook claims that any mail-in ballots arriving after Election Day won’t be counted.

FiveThirtyEight also predicts that the states most likely to be the tipping point in the presidential election are Pennsylvania, Florida, Wisconsin, Michigan, North Carolina, Minnesota, Arizona, Nevada, and Georgia.

Which polls should I trust?

For the highest levels of accuracy, it's best to look to independent polls conducted by third parties that use a random sample. FiveThirtyEight has a helpful tool that aggregates national polls and grades each pollster on its methodology and historical accuracy.

Politicians and campaigns traditionally love to cite internal polls, but these polls should be approached with a healthy amount of skepticism. If an internal poll "leaks," it could be done intentionally and purposefully.

With internal polls, campaigns are able to choose which questions are asked, the wording of the questions, and the order. Additionally, campaigns often neglect to release the polling methodology or the polls in their entirety. Without knowing these specifics, internal polls should not be given too much weight.

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