The US election campaign is in its final weeks and voters go to the polls on November 5th to elect the next president.

Early voting is already underway in a number of states, including battleground areas like North Carolina and Georgia.

With less than three weeks to go until the election, Democratic Vice President Kamala Harris and Republican former President Donald Trump are struggling to win over undecided voters.

However, the popular vote does not decide the winner. Instead, it determines which voters represent each state in the electoral college that elects the president.

To win, a candidate must secure 270 of the 538 votes available. Electoral College votes are distributed among states based on their relative population.

Who is ahead?

According to FiveThirtyEight's daily election poll tracker, Harris is currently leading the national polls, with a 2.4 percentage point lead over Trump.

In July, President Joe Biden, a Democrat, dropped out of the presidential race and endorsed Harris as his successor. Since then, the vice president's ratings have increased compared to lower levels under Biden.

But the race is still close. FiveThirtyEight's election forecast predicts that Harris will be favored to win 54 times out of 100, while Trump will win 46 times out of 100.

Which states could influence the presidential election?

Swing states, also called battleground states, can influence the outcome of a national election.

One of the defining characteristics of a swing state is its unclear political leanings, with no party enjoying overwhelming support.

This year, Arizona, Georgia, Michigan, Nevada, North Carolina, Pennsylvania and Wisconsin are being closely watched.

In the 2020 presidential election, Georgia flipped from Republican red to Democratic blue after nearly three decades of voting Republican, and in Arizona, Democrats won by a narrow margin of 0.3 percentage points.

Polls show Trump and Harris running a tight race in swing states. Polls in these states are more important than national polls in determining the winner because the Electoral College, not the popular vote, decides the president.

What happens if Harris and Trump end in a tie?

There are a total of 538 electoral votes. To win the election, a candidate must score 270.

Because of the way electoral votes are distributed, certain combinations of states could result in a 269-vote tie. Such a scenario is possible, but not likely.

If no candidate receives at least 270 electoral votes, a contingent election is held in which the U.S. House of Representatives decides the winner.

Each state's delegations in the House of Representatives would cast one vote, and a candidate must receive a majority (26 out of 50) of the state delegations' votes to win.

The U.S. Senate would then elect the vice president, with each senator casting one vote and requiring a simple majority (51 votes) to win.

How do surveys work?

Election polls predict how the population might vote by surveying a sample of voters. Surveys are most often conducted over the phone or online. In some cases this will be done by mail or in person.

Survey trackers that aggregate a number of surveys are weighted based on a number of factors, such as: B. the sample size of the survey, the quality of the pollster, the timeliness of the survey and the particular methods used.

How accurate are surveys?

Surveys are never 100 percent accurate. In both the 2016 and 2020 US elections, opinion polls underestimated the popularity of Republican candidates. Although the polls for the 2022 midterm elections are more accurate, many still remain skeptical about the poll results.

Part of the reason polls have been inaccurate in recent years is their ability to reach voters. Surveys are often conducted via telephone survey; However, fewer people are inclined to answer calls. Nonresponse bias is another reason for inaccuracy – for example, Trump voters have chosen not to respond to polls in recent years. Additionally, changes in voter turnout impact the accuracy of polls. For example, voter turnout in 2020 was much higher than expected.

Polls implicitly contain a mathematical margin of error because they use small, select groups of people to determine the choices of a larger population. This margin of error in US polls indicates the range within which the actual result is likely to fall. With a sample size of 1,000 people, the margin of error is approximately plus or minus 3 percent.

Many of the polls conducted before this year's presidential election have shown that the difference in support between Harris and Trump is within the margin of error.