Monmouth released the results of a new poll, in which respondents from Iowa were asked for whom they will vote: Democrat candidate Hillary Clinton or Republican candidate Donald Trump.
Historically, Iowa has been a purple state, in which neither the GOP nor the Democrats have had overwhelming support to clinch that state's electoral college votes. This is why predictions here are of particular importance.
Monmouth poll results
According to the results, 37.0% of respondents intend to cast a ballot for former New York Senator Hillary Clinton, whereas 45.0% intend to cast a ballot for businessman Donald Trump.
The poll was carried out from September 12 to September 14 with 404 likely voters. There is a sampling error of +/-4.9 percentage points. Considering this error margin, the race is currently a statistical tie.
Putting the results in context
As a general rule, however, one should not have too much faith in the results of single polls, since they may incorporate large errors. Instead of relying on results from single polls, forecasting research recommends to rely on combined polls or, even better, a combined forecast that includes different methods and data.
For the following comparison, we translate Clinton's and Trump's raw poll numbers into two-party vote shares. The resulting figures are 45.1% for Clinton and 54.9% for Trump.
Comparison to other polls
An average of recent polls in Iowa has Trump at 52.7% of the two-party vote. Relative to her numbers in the Monmouth poll Trump's poll average is 2.3 percentage points lower. This difference is within the poll's margin of error, which suggests that the poll is not an outlier.
The poll in comparison with PollyVote's prediction
The current PollyVote expects Trump to gain 48.4% of the two-party vote in Iowa. That is, the PollyVote forecast is 6.5 points below her polling numbers. The PollyVote forecast is therefore outside the poll's margin of error.