On October 10, NBC-WSJ-Marist released the results of a new poll, in which respondents from Arizona were asked for whom they will vote: Republican nominee Donald Trump or Democrat nominee Hillary Clinton.
NBC-WSJ-Marist poll results
The results show that 41.0% of respondents would vote for former New York Senator Hillary Clinton, while 42.0% would vote for businessman Donald Trump.
This poll was conducted from September 6 to September 8, among a random sample of 649 likely voters. The margin of error is +/-3.8 points, which means that the levels of voter support for the two candidates do not differ significantly.
Putting the results in context
Single polls should be treated with caution, as they often incorporate large biases. At least, one should check how a poll's results compare to benchmark forecasts.
To make the results comparable to benchmark forecasts, we translate them into two-party vote shares. This procedure results in 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 in an average of recent polls in Arizona. This value is 0.2 percentage points lower than his respective numbers in the NBC-WSJ-Marist poll. This margin is within the poll's margin of error, which means that the poll is not an outlier.
The poll compared with PollyVote's forecast
The latest PollyVote anticipates 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 sampling error indicates that this deviation is insignificant.