美國大選民意調查：誰領先──哈里斯還是川普？

On November 5, voters in the United States will head to the polls to select their next president. This election is particularly significant as it could mark the first time a woman is elected to the highest office in the country. Kamala Harris, the current Vice President, is running against former President Donald Trump, who previously held the presidency. Initially, this election was expected to be a rematch of the 2020 election, but the dynamics shifted dramatically in July when President Joe Biden decided to withdraw from the race and endorse Harris. Now, the central question is whether America will elect its first female president or grant Trump a second term. As election day approaches, we will closely monitor the polls to gauge the candidates' standings and the impact of their campaigns on the race for the White House. Since Kamala Harris announced her candidacy at the end of July, she has maintained a slight lead over Trump in the national polling averages. In the early weeks of her campaign, Harris experienced a surge in her polling numbers, establishing a lead of nearly four percentage points by the end of August. The polling landscape remained relatively stable throughout September and early October, but in recent weeks, the race has tightened, as illustrated by the accompanying charts that display the averages and individual poll results for each candidate. While national polls provide a useful snapshot of a candidate's popularity across the country, they are not the most reliable indicators of the election outcome. This is due to the United States' electoral college system, where each state is allocated a number of votes roughly proportional to its population. A total of 538 electoral college votes are available, and a candidate must secure at least 270 to win the presidency. Although there are 50 states in the US, most tend to consistently vote for the same party, meaning that only a handful of states, known as battleground states or swing states, truly determine the election's outcome. Currently, the leads in these swing states are so narrow that it is challenging to ascertain who is genuinely ahead based solely on polling averages. Polls are designed to broadly reflect public sentiment regarding a candidate or issue, rather than predict election results with precision, especially when the differences are less than a percentage point. Additionally, it is crucial to consider that the individual polls used to calculate these averages have a margin of error of approximately three to four percentage points, indicating that either candidate could be performing better or worse than the current figures suggest. Analyzing the trends since Harris entered the race reveals notable differences among the states. In Arizona, Georgia, Nevada, and North Carolina, the lead has shifted multiple times since early August, but Trump currently holds a slight advantage in all of them. Conversely, in Michigan, Pennsylvania, and Wisconsin, Harris has maintained a lead since August, often by two or three points. However, the polls have tightened significantly, and Trump now has a narrow lead in Pennsylvania. These three states were previously strongholds for the Democratic Party before Trump flipped them in 2016. Biden managed to reclaim them in 2020, and if Harris can do the same, she will be well-positioned to win the election. Notably, on the day Biden exited the race, he was trailing Trump by nearly five percentage points on average across the seven swing states. Pennsylvania is particularly critical for both campaigns, as it boasts the highest number of electoral votes among the seven, making it easier to reach the necessary 270 votes. The polling averages presented in the graphics above are compiled by 538, a reputable organization that collects data from various polling companies. To ensure accuracy, 538 only includes polls from companies that adhere to specific criteria, such as transparency regarding the number of participants, the timing of the poll, and the methodology used (telephone, text message, online, etc. ). It is essential to approach polls with caution, as they have historically underestimated support for Trump in the past two elections. According to polling experts, the national polling error in 2020 was the highest it had been in 40 years. The polling inaccuracies in 2016 were attributed to last-minute voter shifts and an overrepresentation of college-educated voters in polling samples. In 2020, experts noted difficulties in engaging Trump supporters in polls, but the exact causes of the polling errors remain uncertain, especially given the pandemic's impact on the election and the record voter turnout. Pollsters have implemented numerous changes since then, and the polling industry experienced one of its most successful election cycles in US history during the 2022 midterm elections. However, it is important to note that Trump was not on the ballot during the midterms, and we will only know after election day whether these adjustments can effectively address the unique challenges posed by the influx of irregular voters that Trump tends to attract.