Bloomberg balances pool size, methods

As the presidential election season comes to a close, it seems that voters are inundated with confusing and deceitful polls. Polls shouldn’t be taken at face value. Factors like sample size, population representation and pollster bias can all affect poll accuracy

How the Poll is Conducted

Consider The Bloomberg Poll, a longstanding source for political coverage, uses an automated dialing method to conduct live telephone interviews. This method randomizes phone numbers on landlines and cellphones for live callers to dial. These phone numbers are supplied by the market research company Survey Sampling International. The callers ask interviewees an extensive list of questions about the current election. Questions include:

·      If the general election were held today, and the candidates were [Hillary Clinton for the Democrats] and [Donald Trump for the Republicans], for whom would you vote?

·      In general, do you think things in the nation are headed in the right direction, or have they gotten off on the wrong track?

·      Which of the following do you see as the most important issue facing the country right now? 

Using live callers can make respondents more comfortable and is an alternative to automated polls where the participant keys in responses to recorded questions. Automated voice response systems have been found to record faulty responses and return low response rates. People are much less likely to respond to a computer than a human voice.

Because Bloomberg uses live callers, their poll is more time consuming and costly. Bloomberg polls conducted in the current election season show an average sample size of 1,000 interviews. One thing that limits the sample size is a federal regulation requiring that cellphone numbers be dialed manually to limit spam calling.

Cell phone interviews are important for ensuring that those called represent Americans well. Young adults and Americans in poverty may only have a cell phone. Another way to ensure proper representation is to weight responses. Weighting factors can include age, race and level of education. Polling firms will select people according to these characteristics in order to have the sample match the known demographics of the population they are questioning.

Bias in Polls

Another important factor is poll sponsorship. Organizations with political or religious agendas may use flawed methodology to provide results consistent with their ideology. The Bloomberg Poll is overseen by Selzer & Company, a public opinion research company led by famed pollster J. Ann Selzer. Selzer & Company provides polling research to various news media outlets such as the Iowa Newspaper Association, The Newspaper Association of America and the American Press Institute. J. Ann Selzer’s client list can help us evaluate any political leaning tendencies.

Pollster watch dogs can also provide us with insight into polling bias. The political and pop culture news site FiveThirtyEight relies on statistical analysis for storytelling. Founder Nate Silver has rated dozens of polls in an effort to expose polling inaccuracy. Selzer & Company polls were given an A+ rating, citing that 84% of the Selzer polls analyzed were called correctly. These ratings can help us compare polls to achieve a better understanding of bias.

by Rachyl Jackson