NBC-WSJ-Marist published the results of a new poll. In this poll, interviewees from Ohio were asked for whom they will vote: Hillary Clinton or Donald Trump.
Ohio is traditionally a battleground state, where the Democrats and the GOP have often achieved similar levels of support among voters. This is why the election outcome in that state is viewed as important in determining the overall result of the presidential election.
NBC-WSJ-Marist poll results
Of those who responded, 43.0% said that they would vote for former New York Senator Hillary Clinton, while 38.0% said that they would give their vote to real estate developer Donald Trump.
The poll was conducted from August 3 to August 7 among 889 registered voters. The sampling error is +/-3.3 percentage points. This means that the poll results for the two candidates do not differ significantly.
Putting the results in context
Single polls can contain substantial errors, and should be treated with caution. At the very least, one should examine how a poll's results compare to benchmark forecasts.
For the following analysis, we convert Clinton's and Trump's raw poll numbers into shares of the two-party vote. This procedure yields figures of 53.1% for Clinton and 46.9% for Trump. On August 28 Clinton obtained only 46.9% in the NBC-WSJ-Marist poll and Trump obtained only 0.0%.
Comparison to other polls
Looking at an average of Ohio polls, Clinton's current two-party vote share is at 52.2%. In comparison to her numbers in the NBC-WSJ-Marist poll Clinton's poll average is 0.9 percentage points worse. This difference is within the poll's error margin, which suggests that the poll is not an outlier.
Results compared to the combined PollyVote forecast
The current PollyVote expects Clinton to gain 52.0% of the two-party vote in Ohio. That is, Polly's prediction is 1.1 points below her polling numbers. The PollyVote forecast is thus within the poll's margin of error.