PPP (D) released the results of a new poll, in which respondents from Pennsylvania were asked for whom they will vote: Donald Trump or Hillary Clinton.
PPP (D) poll results
The results show that 49.0% of participants indicated to vote for former First Lady Hillary Clinton, whereas 45.0% would vote for businessman Donald Trump.
The poll was conducted between July 29 and July 31. The sample size was 1505 likely voters. Taking into account the poll's sampling error of +/-2.5 percentage points, the results reflect a statistical tie.
Putting the results in context
As any other method, polls are subject to bias. Therefore, as a general rule, you should not put too much trust in the results of a single poll. Instead of relying on results from single polls, the recommended strategy use combined polls or, even better, the combined PollyVote forecast that uses forecasts from different methods, each of which draws upon different data.
For the following analysis, we convert the candidates' raw poll numbers into shares of the two-party vote. This yields figures of 52.1% for Clinton and 47.9% for Trump. In the latest PPP (D) poll on August 1 Clinton obtained 52.3%, while Trump obtained only 47.7%.
Comparison to other polls
Looking at an average of Pennsylvania polls, Clinton's two-party vote share is currently at 55.1%. This value is 3.0 percentage points higher than her respective numbers in the PPP (D) poll. This margin is outside the poll's margin of error, which suggests that the poll is an outlier.
Comparison to the combined PollyVote
The current PollyVote foresees Clinton to gain 53.3% of the two-party vote in Pennsylvania. Hence, the PollyVote forecast is 1.2 points above her polling numbers. Again, a look at the poll's sampling error indicates that this deviation is insignificant.