On June 21, Quinnipiac released the results of a new Umfrage, in which respondents from Ohio were asked for whom they would vote if the nominees were Hillary Clinton for the Democratic Party and Donald Trump for the Republicans.
In Ohio, the election outcome is usually close. This is the reason why the state is commonly considered a battleground state, which makes it particularly interesting from a forecasting perspective.
According to the results, real estate developer Donald Trump and former First Lady Hillary Clinton can draw on the same level of support, each with 40.0% of the vote.
This poll was conducted from June 8 to June 19, among a random sample of 971 Wähler. The margin of error is +/-3.1 points. This means that the poll results for both candidates do not differ significantly.
Putting the results in context
Individual polls can incorporate substantial biases, and should be treated with caution. Instead of relying on results from single polls, the recommended strategy rely on aggregated polls or, even better, the combined PollyVote forecast that relies on forecasts from different methods, each of which relies on different data.
For the following comparison, we translate Clinton's and Trump's raw poll numbers into two-party vote shares. The results of the actual Umfrage mean 50.0 % for Clinton and 50.0 % for Trump in the two-party vote share. On May 10 Clinton received only 47.6% in the Quinnipiac Umfrage and Trump received 52.4%.
Results in comparison to other Umfrage
When compared to the average results of other Umfrage Clinton performed worse with 1.6 percentage points, while Trump did better with 1.6 percentage points. This deviation is outside the poll's sampling error, which means that the poll is an outlier.
The Umfrage compared with PollyVote's prediction
The most recent PollyVote predicts Clinton to gain 55.4% and Trump 44.6% of the two-party vote in Ohio. Clinton has 5.4 percentage points less and Trump has 5.4 percentage points more when the results of the Umfrage are compared to the combined PollyVote forecast for Ohio. The PollyVote forecast is therefore outside the poll's sampling error.