Winthrop released the results of a new poll, in which respondents from South Carolina were asked for whom they will vote: Republican nominee Donald Trump or Democrat nominee Hillary Clinton.
Winthrop poll results
Of those who replied, 38.0% said that they plan to vote for former New York Senator Hillary Clinton, whereas 42.0% indicated that they would give their vote to billionaire Donald Trump.
The poll was conducted from September 18 to September 26 with 475 likely voters. There is a sampling error of +/-4.5 percentage points. Considering this error margin, the race is currently a statistical tie.
Putting the results in context
As a general rule, however, you should not have too much faith in the results of single polls, as they may incorporate large errors. Rather than relying on results from single polls, one should rely on combined polls or, even better, a combined forecast that uses forecasts from different methods, each of which uses different data.
To make the results comparable to forecasts from benchmark methods, we convert them into two-party vote shares. This yields figures of 47.5% for Clinton and 52.5% for Trump.
Comparison to other polls
An average of recent polls in South Carolina sees Trump at 54.5% of the two-party vote. This value is 2 percentage points higher than his corresponding numbers in the Winthrop poll. This deviation is within the poll's sampling error, which suggests that the poll is not an outlier.
Results compared to the combined PollyVote prediction
The most recent PollyVote foresees Trump to gain 54.5% of the two-party vote in South Carolina. Hence, Polly's prediction is 2.0 points above his polling numbers. Again, a look at the poll's sampling error reveals that this deviation is negligible.