Results of a new poll conducted by NBC-WSJ-Marist were circulated. The poll asked respondents from Pennsylvania for whom they will vote: Donald·Trump or Hillary·Clinton.
NBC-WSJ-Marist poll results
According to the results, 48.0% of respondents said that they would cast a ballot for former New York Senator Hillary Clinton, whereas 37.0% would vote for billionaire Donald Trump.
This poll was conducted from August 3 to August 7, among a random sample of 834 registered voters. The error margin is +/-3.4 percentage points, which means that the poll results for the Democratic and the Republican candidate differ significantly.
Putting the results in context
Individual polls often contain substantial errors, and should be treated with caution. Instead of relying on results from single polls, research in forecasting recommends to use combined polls or, even better, a combined forecast that includes forecasts from different methods, each of which includes different data.
For the following comparison, we translate the candidates' raw poll numbers into two-party vote shares. This yields figures of 56.5% for Clinton and 43.5% for Trump.
Comparison to other polls
Clinton can currently count on 55.2% of the two-party vote according to an average of recent polls in Pennsylvania. In comparison to her numbers in the NBC-WSJ-Marist poll Clinton's poll average is 1.3 percentage points worse. This difference is within the poll's sampling error, which means that the poll is not an outlier.
The poll compared with PollyVote's prediction
The latest PollyVote anticipates Clinton to gain 53.4% of the two-party vote in Pennsylvania. This means that Polly's forecast is 3.1 points below her polling numbers. The PollyVote forecast is therefore in line with the poll's error margin.