Results of a new poll conducted by NBC-WSJ-Marist were published. The poll asked interviewees from Pennsylvania for whom they will vote: Republican Donald Trump or Democrat Hillary Clinton.
NBC-WSJ-Marist poll results
The results show that 48.0% of participants would cast a ballot for former New York Senator Hillary Clinton, while 37.0% plan to vote for businessman Donald Trump.
The poll was carried out from August 3 to August 7 with 834 registered voters. Taking into account the poll's margin of error 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, a good strategy is to not be overly confident the results of a single poll. Rather, one should examine how a poll's results compare to benchmark forecasts.
To make the results comparable to benchmark forecasts, one can convert them into shares of the two-party vote. The resulting figures are 56.5% for Clinton and 43.5% for Trump.
Comparison to other polls
An average of recent polls in Pennsylvania sees Clinton at 54.5% of the two-party vote. This value is 2 percentage points lower than her corresponding numbers in the NBC-WSJ-Marist poll. This margin is within the poll's margin of error, which suggests that the poll is not an outlier.
Results compared to the combined PollyVote forecast
The most recent PollyVote expects Clinton to gain 54.4% of the two-party vote in Pennsylvania. That is, Polly's prediction is 2.1 points below her polling numbers. The PollyVote forecast is therefore in line with the poll's error margin.