PPP (D) published the results of a new poll. In this poll, interviewees from Pennsylvania were asked for whom they will vote: Democrat Hillary Clinton or Republican Donald Trump.
PPP (D) poll results
The results show that 49.0% of respondents plan to vote for former Secretary of State Hillary Clinton, while 45.0% would vote for businessman Donald Trump.
This poll was conducted from July 29 to July 31, among a random sample of 1505 likely voters. There is a sampling error of +/-2.5 percentage points. Considering this error margin, the race is currently a statistical tie.
Putting the results in context
Single polls can incorporate substantial biases, which is why they should be interpreted with caution. Rather than trusting the results from single polls, the best practice scientific advice is to rely on combined polls or, even better, a combined forecast that incorporates forecasts from different methods, each of which draws upon different data.
To make the results comparable to forecasts from benchmark methods, one can translate them into two-party vote shares. This procedure results in figures of 52.1% for Clinton and 47.9% for Trump.
Comparison to other polls
If we look at an average of Pennsylvania polls, Clinton's two-party vote share is currently at 55.1%. Relative to her numbers in the PPP (D) poll Clinton's poll average is 3 percentage points higher. This difference is outside the poll's error margin, which suggests that the poll is an outlier.
Results compared to the combined PollyVote prediction
The most recent PollyVote foresees Clinton to gain 54.6% of the two-party vote in Pennsylvania. That is, Polly's combined forecast is 2.5 points above her polling numbers. The PollyVote forecast is therefore within the poll's sampling error.