NBC-WSJ-Marist published the results of a new poll. In this poll, interviewees from Illinois were asked for whom they will vote: Republican Donald Trump or Democrat Hillary Clinton.
NBC-WSJ-Marist poll results
Of those who answered the question, 57.0% said that they will vote for former Secretary of State Hillary Clinton, while 32.0% indicated that they would give their vote to real estate developer Donald Trump.
The poll was conducted from March 4 to March 10 among 1968 registered voters. There is a sampling error of +/-2.2 percentage points. Considering this error margin, the gap between both candidates is statistically significant.
Putting the results in context
Individual polls may include substantial biases, which is why they should be treated with caution. Rather than trusting the results from single polls, the evidence-based approach is to rely on combined polls or, even better, a combined forecast that uses different methods and data.
For the following analysis, we convert Clinton's and Trump's raw poll numbers into shares of the two-party vote. The corresponding figures are 64.0% for Clinton and 36.0% for Trump.
Results compared to the combined PollyVote forecast
The latest PollyVote anticipates Clinton to gain 58.2% of the two-party vote in Illinois. This means that Polly's combined forecast is 5.8 points below her polling numbers. Again, a look at the poll's sampling error indicates that this deviation is significant.