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 result in either Donald Trump securing a second term or Kamala Harris making history as the first woman president of the United States. Initially, this election was expected to be a rematch of the 2020 election, but the dynamics shifted dramatically in July when President Joe Biden announced the end of his campaign and endorsed Vice-President Kamala Harris. As election day draws near, the central question remains: who will emerge victorious? We will closely monitor the polls and assess the impact of major events, such as the upcoming presidential debate, on the race for the White House. In the months leading up to Biden's withdrawal from the race, polls consistently indicated that he was trailing former President Trump. Some polls even suggested that Harris might not perform significantly better. However, the race began to tighten once she hit the campaign trail, and she has since developed a slight lead over Trump in the average of national polls. The latest polling averages indicate that Harris is currently at approximately 47%, while Trump hovers around 44%. Harris's numbers have remained relatively stable since her party's four-day convention in Chicago, where she concluded the event with a speech that promised a 'new way forward' for all Americans. Trump's average has also shown little fluctuation, and he did not experience a notable boost from the endorsement of Robert F. Kennedy, who ended his independent candidacy shortly after Harris's convention. While national polls serve as a useful gauge of a candidate's popularity across the country, they do not necessarily provide an accurate prediction of the election outcome. This is due to the fact that the United States employs an electoral college system to elect its president, meaning that winning the most votes is not always the most critical factor; rather, it is essential to consider where those votes are cast. The US consists of 50 states, but many of them consistently vote for the same party. Consequently, only a select few states are truly competitive and can determine the election's outcome. These states are referred to as battleground states. Presently, the polls indicate a very close race in seven battleground states, making it challenging to ascertain who is genuinely leading. There are fewer state polls available compared to national polls, resulting in limited data for analysis. In several states, the margin between the two candidates is less than one percentage point. This is particularly true in Pennsylvania, which is crucial due to its high number of electoral votes, making it easier for the winner to reach the necessary 270 votes. Pennsylvania, Michigan, and Wisconsin were once strongholds for the Democratic Party, but Trump flipped them to Republican in 2016. Biden managed to reclaim these states in 2020, and if Harris can achieve the same this year, she will be well-positioned to win the election. The dynamics of the race have shifted since Harris became the Democratic nominee. On the day Biden exited the race, he was trailing Trump by nearly five percentage points on average in these seven battleground states. The averages presented in the graphics above are compiled by 538, a part of the American news network ABC News. To create these averages, 538 gathers data from individual polls conducted both nationally and in battleground states by various polling organizations. As part of their quality control measures, 538 only includes polls from companies that adhere to specific criteria, such as transparency regarding the number of respondents, the timing of the poll, and the methodology used (telephone calls, text messages, online surveys, etc. ). Currently, the polls suggest that Kamala Harris and Donald Trump are within a couple of percentage points of each other, both nationally and in battleground states. When the race is this close, it becomes exceedingly difficult to predict the winner. Polls have historically underestimated support for Trump in both the 2016 and 2020 elections. Polling companies are actively working to address this issue in various ways, including refining their methods to better reflect the composition of the voting population. However, these adjustments are complex, and pollsters must still make educated guesses about factors such as voter turnout on November 5.