Results of a new poll conducted by PPICPPIC were circulated. The poll asked participants from California for whom they will vote: Republican Donald Trump or Democrat Hillary Clinton.
PPICPPIC poll results
According to the results, 46.0% of participants said that they would cast a ballot for former First Lady Hillary Clinton, while 30.0% said that they would cast a ballot for businessman Donald Trump.
The poll was conducted from July 10 to July 19 among 1056 likely voters. If one accounts for the poll's error margin of +/-4.3 percentage points, the spread between both candidates is statistically significant.
Putting the results in context
As any other method, polls are subject to bias. Thus, as a general rule, one should not focus too much on the results of a single poll. Rather, one should examine how a poll's results compare to benchmark forecasts.
For the following comparison, we convert Trump's and Clinton's raw poll numbers into shares of the two-party vote. This procedure yields values of 60.5% for Clinton and 39.5% for Trump.
Comparison to other polls
Clinton currently runs at 63.3% of the two-party vote in an average of recent polls in California. In comparison to her numbers in the PPICPPIC poll Clinton's poll average is 2.8 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 current PollyVote predicts Clinton to gain 61.3% of the two-party vote in California. That is, Polly's forecast is 0.8 points above her polling numbers. Again, a look at the poll's sampling error indicates that this difference is negligible.