Everything you need to know about election polls in 2020

• Democratic nominee Joe Biden has about a 10 percentage point lead over President Donald Trump in an average of national polls before Election Day.
• 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.

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.

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 4.8 percentage points in state polls, according to FiveThirtyEight, and DDHQ predicts Biden has a 74.5% chance of winning the Keystone State given that lead.

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 2.5 points and DDHQ suggests he has a 63% 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.

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 two and three percentage 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 Iowa, Ohio, and Texas.

Polling in swing states on the eve of the election:

• An average of recent polls in Texas estimate that Trump is leading in the Lone Star State by just one 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 2 percentage 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 0.6 percentage points in the polls.
• In Georgia, Biden currently leads in the polls by about 1-1.2 percentage points, according to FiveThirtyEight. Conversely, RealClearPolitics estimates that Trump is currently leading in the state by just 0.2 points. The state has not voted for a Democratic nominee since President Bill Clinton in 1992.
• In Iowa, an average of polls estimates Trump is in the lead by up to 1.2 percentage points over Biden. 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 2.6 percentage points in the polls. Trump won the state in 2016 by 3.5 points.
• Trump currently trails Biden by an average of 2.5 percentage points in Florida, but the race may be even closer as RealClearPolitics estimates Biden is up by just 1.7 percentage points.
• In Pennsylvania, Biden leads Trump by an average of 4.8 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 8.2 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.

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.