NBC-WSJ-Marist published the results of a new poll. In this poll, participants from Pennsylvania were asked for whom they will vote: Republican Donald Trump or Democrat Hillary Clinton.
NBC-WSJ-Marist poll results
Of those who replied, 48.0% said that they will vote for former New York Senator Hillary Clinton, whereas 37.0% declared that they would give their vote to billionaire Donald Trump.
The poll was conducted from August 3 to August 7 with 834 registered voters. Given the poll's error margin of +/-3.4 percentage points, the difference in voter support is statistically significant.
Putting the results in context
As any other method, polls are subject to bias. Therefore, as a general rule, one should not have too much faith in the results of a single poll. Rather than relying on results from single polls, forecasting research recommends to use combined polls or, even better, the combined PollyVote forecast that includes different methods and data.
For the following analysis, we convert Trump's and Clinton's raw poll numbers into two-party vote shares. This yields figures of 56.5% for Clinton and 43.5% for Trump.
Results vs. other polls
Looking at an average of Pennsylvania polls, Clinton's current two-party vote share is at 55.2%. Compared to her numbers in the NBC-WSJ-Marist poll Clinton's poll average is 1.3 percentage points lower. This margin is within the poll's margin of error, which means that the poll is not an outlier.
The poll in comparison with PollyVote's prediction
The most recent PollyVote predicts Clinton to gain 54.6% of the two-party vote in Pennsylvania. That is, the combined PollyVote is 1.9 points below her polling numbers. Again, a look at the poll's error margin shows that this deviation is insignificant.