Marquette published the results of a new poll. In this poll, respondents from Wisconsin were asked for whom they will vote: Republican Donald Trump or Democrat Hillary Clinton.
Marquette poll results
Of those who replied, 44.0% said that they are going to vote for former New York Senator Hillary Clinton, while 42.0% declared that they would give their vote to real estate developer Donald Trump.
The poll was conducted from September 15 to September 18. A total of 677 likely voters responded. Taking into account the poll's sampling error of +/-4.8 percentage points, the results reflect a statistical tie.
Putting the results in context
In general, however, a good strategy is to not have too much faith in the results of single polls, as they may incorporate large errors. At the very least, one should check how a poll's results compare to benchmark forecasts.
In order to make the results comparable to benchmark forecasts, we convert them into two-party vote shares. This yields figures of 51.2% for Clinton and 48.8% for Trump. To compare: 56.0% was gained by Clinton in the Marquette poll on March 28, for Trump this number was only 44.1%.
Results in comparison to other polls
Looking at an average of Wisconsin polls, Clinton's two-party vote share is currently at 52.9%. Compared to her numbers in the Marquette poll Clinton's poll average is 1.7 percentage points better. This deviation is within the poll's sampling error, which means that the poll is not an outlier.
The poll in comparison with PollyVote's prediction
The current PollyVote predicts Clinton to gain 53.8% of the two-party vote in Wisconsin. This means that the PollyVote is 2.6 points above her polling numbers. Again, a look at the poll's error margin suggests that this difference is insignificant.