Results of a new poll conducted by NBC-WSJ-Marist were spread. The poll asked interviewees from Arizona for whom they will vote: Democrat candidate Hillary Clinton or Republican candidate Donald Trump.
NBC-WSJ-Marist poll results
Of those who answered the question, 41.0% said that they will vote for former First Lady Hillary Clinton, while 42.0% said that they would give their vote to businessman Donald Trump.
This poll was conducted from September 6 to September 8, among a random sample of 649 likely voters. The sampling error is +/-3.8 points, which means that the levels of voter support for the Democratic and the Republican candidate do not differ significantly.
Putting the results in context
Individual polls should be interpreted with caution, because they often include large errors. Instead of trusting the results from single polls, the best practice scientific advice is to rely on combined polls or, even better, the combined PollyVote forecast that incorporates forecasts from different methods, each of which draws upon different data.
In order to make the results comparable to forecasts from other methods, one can translate them into two-party vote shares. This yields figures of 49.4% for Clinton and 50.6% for Trump.
Results in comparison to other polls
If we look at an average of Arizona polls, Trump's two-party vote share is currently at 49.1%. Relative to her numbers in the NBC-WSJ-Marist poll Trump's poll average is 1.5 percentage points worse. This margin is within the poll's error margin, which means that the poll is not an outlier.
Results compared to the combined PollyVote prediction
The current PollyVote expects Trump to gain 51.3% of the two-party vote in Arizona. That is, Polly's combined forecast is 0.7 points above her polling numbers. Again, a look at the poll's sampling error shows that this deviation is negligible.