FOX News published the results of a new poll on August 1. In this poll, participants from Colorado were asked for whom they will vote: Hillary Clinton or Donald Trump.
In Colorado, the election outcome is often decided by a narrow margin. This is the reason why the state is commonly considered a swing state, which makes it particularly interesting from a forecasting perspective.
FOX News poll results
The results show that 44.0% of participants indicated that they would cast a ballot for former Secretary of State Hillary Clinton, whereas 34.0% are going to vote for real estate developer Donald Trump.
The poll was conducted between July 9 and July 12. The sample size was 600 registered voters. There is a sampling error of +/-4.0 percentage points. Considering this error margin, the gap between both candidates is statistically significant.
Putting the results in context
As a general rule, however, one should not have too much faith in the results of single polls, as they can contain large errors. Instead of relying on results from single polls, one should use combined polls or, even better, a combined forecast that draws upon forecasts from different methods, each of which draws upon different data.
For the following comparison, we convert Clinton's and Trump's raw poll numbers into two-party vote shares. The corresponding figures are 56.4% for Clinton and 43.6% for Trump.
Comparison to other polls
Looking at an average of Colorado polls, Clinton's current two-party vote share is at 54.9%. In comparison to her numbers in the FOX News poll Clinton's poll average is 1.5 percentage points worse. This difference is within the poll's error margin, which means that the poll is not an outlier.
The poll compared with PollyVote's prediction
The current PollyVote predicts Clinton to gain 53.1% of the two-party vote in Colorado. That is, Polly's combined forecast is 3.3 points below her polling numbers. Again, a look at the poll's sampling error indicates that this deviation is negligible.