On July 27, CBS released the results of a new national poll sponsored by CBS, in which respondents were asked for whom they will vote: Donald Trump or Hillary Clinton.
CBS poll results
According to the results, 44.0% of interviewees said that they are going to vote for former Secretary of State Hillary Clinton, whereas 43.0% are going to vote for businessman Donald Trump.
The poll was carried out via phone from July 22 to July 24 among 1118 participants. If one takes into account the poll's margin of error of +/-4.0 percentage points, the results reflect a statistical tie.
Putting the results in context
As any other method, polls are subject to bias. Thus, as a general rule, you should not focus too much on the results of a single poll. Rather than trusting the results from single polls, forecasting research recommends to consult combined polls or, even better, a combined forecast that uses forecasts from different methods, each of which uses different data.
For the following analysis, we convert Clinton's and Trump's raw poll numbers into shares of the two-party vote. This procedure results in figures of 49.4% for Clinton and 50.6% for Trump. To compare: Only 45.6% was gained by Clinton in the CBS poll on July 26, for Trump this result was 54.4%.
Results in comparison to other polls
An average of recent polls has Trump at 49.5% of the two-party vote. In comparison to his numbers in the CBS poll Trump's poll average is 1.1 percentage points lower. This margin is within the poll's sampling error, which means that the poll is not an outlier.
Comparison to the combined PollyVote
The current PollyVote expects Trump to gain 48.1% of the two-party vote. This means that the PollyVote forecast is 2.5 points below his polling numbers. The PollyVote forecast is thus in line with the poll's sampling error.