An analysis of Ohioan polls — the most-polled state in the country, having been polled 44 times this election season — shows an interesting trend; polls with live interviewers typically favor current President Barack Obama by a greater degree than automated polls.
Talking Points Memo did an analysis of the two different methods of polling and came up with some very interesting results: “Since early September, live polls have shown Obama with an average lead of 4.5 percent in Ohio while robo-polls show him with an average lead of less than 2,” they report, showing yet another way polls can be inherently biased. They provide a chart (seen below) to further emphasize the distinction.
The chart below looks at Obama’s leads in live polls compared to the robo-polls since the end of the Democratic National Convention on Sept. 6. Any dip below 0 percent represents a lead for Republican nominee Mitt Romney:
Automated polls cannot legally call cell phones, so they only call landlines. That results in a natural skew toward an older demographic. Not only that, but cell phone users (although a live interviewer will call both types) represent a truer cross-section of the country as a whole; nearly everyone in America has a cell phone.
Charles Franklin, the director of the Marquette University Law School Poll and co-founder of Pollster.com, explained that surveys conducted by live callers remain the preferred method because they are able to reach a more accurate sample of voters.
“The response rates to automated polls are naturally a good deal lower than live interview polls. Both have low response rates, but automated are quite a bit less,” Franklin told TPM. “The lower the response rate, the more likely you are to get a more involved, interested and motivated sample. That shows up in a higher probability of voting, but might show up with lower undecideds.”
Automated polls are still very common and will likely remain so because of the lower amount of manpower necessary to conduct the interview. Automated polls also have the advantage of being conducted quickly in comparison to live interviewer polls. However, with such an obvious difference in poll results, should pollsters perhaps find another way?