Results of a new poll administered by PPIC were released. The poll asked participants from California for whom they will vote: Republican nominee Donald Trump or Democrat nominee Hillary Clinton.
PPIC poll results
The results show that 47.0% of respondents are going to cast a ballot for former Secretary of State Hillary Clinton, whereas 31.0% intend to vote for billionaire Donald Trump.
The poll was carried out between September 9 and September 18. The sample size was 1055 likely voters. Given the poll's sampling error of +/-4.5 percentage points, the spread in voter support is statistically significant.
Putting the results in context
Individual polls should be interpreted with caution, since they can incorporate large errors. Rather than trusting the results from single polls, forecasting research recommends to look at combined polls or, even better, the combined PollyVote forecast that incorporates different methods and data.
To make the results comparable to forecasts from other methods, you can convert them into shares of the two-party vote. This procedure yields values of 60.3% for Clinton and 39.7% for Trump.
Results vs. other polls
An average of recent polls in California has Clinton at 61.7% of the two-party vote. In comparison to her numbers in the PPIC poll Clinton's poll average is 1.4 percentage points better. This difference is within the poll's margin of error, which suggests that the poll is not an outlier.
Comparison to the combined PollyVote
The latest PollyVote predicts Clinton to gain 61.0% of the two-party vote in California. That is, Polly's prediction is 0.7 points above her polling numbers. Again, a look at the poll's sampling error reveals that this difference is insignificant.