Lest you think I’m simply lazing about all summer in Maine, I’m doing far more than that. I’m writing letters to the editor.
Here’s my letter addressing a problem with a poll in the Portland (Me.) Press Herald:
In Tuesday’s front-page article about a recent Rasmussen poll, the newspaper states that Paul LePage “leads the race” with support from 39 percent of respondents compared to 31 percent for Elizabeth Mitchell. The poll’s margin of error is plus or minus 4.5 percent.
Because of the intricacies of statistical modeling, the margin of error means that LePage’s true support could be as low as 34.5 percent and Mitchell’s could be as high as 35.5 percent. Therefore, LePage and Mitchell are actually in a statistical dead heat.
According to the article, Rasmussen surveyed 500 people for the poll. In order to achieve a lower margin of error (in the 3 percent range), approximately 1,000 people would need to be interviewed.
Of course, interviewing twice as many respondents would cost a lot more money — which is why we see a lot of polls with large margins of error.
The Press Herald is surely not alone in this oversight. Research has found that many media outlets tend to ignore or downplay the details of polling margins.
In the future, reporters should be careful how they phrase poll results, and editors may want to be more selective in which polls they choose to highlight.
Matt J. Duffy, Ph.D.
That’s my first official use of the Ph.D. They took out the following coda: “Duffy teaches journalism at Zayed University in Abu Dhabi, UAE. He summers in Maine.”