KABC/SurveyUSA published the results of a new poll. In this poll, interviewees from California were asked for whom they will vote: Republican nominee Donald Trump or Democrat nominee Hillary Clinton.
KABC/SurveyUSA poll results
Of those who answered the question, 57.0% said that they will vote for former First Lady Hillary Clinton, whereas 32.0% said that they would give their vote to businessman Donald Trump.
The poll was conducted from September 8 to September 11. A total of 678 likely voters responded. Given the poll's sampling error of +/-3.8 percentage points, the difference in voter support is statistically significant.
Putting the results in context
As a general rule, however, don't have too much faith in the results of single polls, since they sometimes incorporate large errors. Instead of relying on results from single polls, research in forecasting recommends to use combined polls or, even better, a combined forecast that uses different methods and data.
To make the results comparable to forecasts from other methods, one can translate them into shares of the two-party vote. This procedure results in values of 64.0% for Clinton and 36.0% for Trump.
Comparison to other polls
An average of recent polls in California sees Clinton at 64.1% of the two-party vote. Relative to her numbers in the KABC/SurveyUSA poll Clinton's poll average is 0.1 percentage points better. This difference is within the poll's sampling error, which suggests that the poll is not an outlier.
The poll in comparison with PollyVote's forecast
The most recent PollyVote anticipates Clinton to gain 61.5% of the two-party vote in California. That is, the PollyVote forecast is 2.5 points below her polling numbers. Again, a look at the poll's margin of error suggests that this difference is insignificant.