NBC-WSJ-Marist published the results of a new poll. In this poll, interviewees from Ohio were asked for whom they will vote: Republican nominee Donald Trump or Democrat nominee Hillary Clinton.
Ohio is traditionally a purple state, where the GOP and the Democrats have historically won similar voter support. Therefore, the election outcome in that state is viewed as important in determining who will win the majority of electoral votes.
NBC-WSJ-Marist poll results
Of those who replied, 43.0% said that they plan to 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 carried out from August 3 to August 7 with 889 registered voters. The error margin is +/-3.3 points, which means that the levels of voter support for the two candidates do not differ significantly.
Putting the results in context
As a general rule, however, don't have too much faith in the results of single polls, since they often incorporate large errors. Rather than relying on results from single polls, forecasting research recommends to rely on combined polls or, even better, the combined PollyVote forecast that uses forecasts from different methods, each of which draws upon different data.
For the following analysis, we convert Trump's and Clinton's raw poll numbers into two-party vote shares. The respective figures are 53.1% for Clinton and 46.9% for Trump.
Results vs. other polls
If we look at an average of Ohio polls, Clinton's current two-party vote share is at 51.7%. Relative to her numbers in the NBC-WSJ-Marist poll Clinton's poll average is 1.4 percentage points lower. This difference is within the poll's sampling error, which means that the poll is not an outlier.
Comparison to the combined PollyVote
The current PollyVote forecasts Clinton to gain 52.0% of the two-party vote in Ohio. Hence, the PollyVote is 1.1 points below her polling numbers. The PollyVote forecast is thus in line with the poll's error margin.