Results of a new poll conducted by NBC-WSJ-Marist were spread. The poll asked respondents from Arizona for whom they will vote: Hillary Clinton or Donald Trump.
NBC-WSJ-Marist poll results
Of those who answered the question, 41.0% said that they plan to vote for former First Lady Hillary Clinton, while 42.0% indicated 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. There is a sampling error of +/-3.8 percentage points. Considering this error margin, the race is currently a statistical tie.
Putting the results in context
Single polls may incorporate substantial biases, which is why they should be interpreted with caution. Rather than relying on results from single polls, you should rely on combined polls or, even better, a combined forecast that relies on forecasts from different methods, each of which draws upon different data.
For the following comparison, we translate Clinton's and Trump's raw poll numbers into two-party vote shares. This yields figures of 49.4% for Clinton and 50.6% for Trump.
Comparison to other polls
Trump currently achieves 50.4% of the two-party vote according to an average of recent polls in Arizona. Relative to his numbers in the NBC-WSJ-Marist poll Trump's poll average is 0.2 percentage points lower. This margin is within the poll's error margin, which means that the poll is not an outlier.
Results compared to the combined PollyVote forecast
The most recent PollyVote forecasts Trump to gain 53.2% of the two-party vote in Arizona. Hence, Polly's prediction is 2.6 points above his polling numbers. Again, a look at the poll's margin of error reveals that this difference is negligible.