A loudly touted Franklin and Marshall College poll of likely Pennsylvania voters showing Democrat Hillary Clinton 11 points ahead of Republican Donald Trump polled Democrats by eight percentage points more than Republicans.
According to the survey October survey that was released on Tuesday, Clinton leads Trump 49 percent to 38 percent among likely voters.
Of the 863 registered voters, 48 percent were Democrats, 38 percent were Republicans, and only 14 percent were independents.
— F&M Opinion Research (@FandMPoll) November 1, 2016
Franklin and Marshall goes on to say of their polling methodology that “The current survey shows 50% self-identified as Democrat and 42% self-identified as Republican, providing Democrats with a plus 8 self-identification advantage.”
“Respondents to our poll are able to choose whether to respond by telephone (n=449) or using an on-line survey (n=414). There are sizable differences in the characteristics of respondents depending on their choice of survey mode (seeFigure 5). The web respondents are more likely to be younger, better educated, and more liberal than telephone respondents although there is no difference in terms of party affiliation or likelihood of voting. These demographic differences result in both Democratic candidates performing better among web-respondents than among telephone respondents.”
Franklin and Marshall also notes that the survey used a list of of Pennsylvania registered voters as its sample frame and that a limitation of a list of this kind is that not every voters on the list has a listed telephone number.
“The methodology we use allows a voter with no telephone number to be included in our surveys—in this sample 87 of our 863 respondents had no listed phone number. These unmatched respondents appeared more supportive of Secretary Clinton (54% to 35%) than did respondents with matched telephone numbers (48% to 37%).”
Additionally, the polling was performed prior FBI director James Comey’s announcement that the agency would be re-examing Clinton’s private email server case after finding more emails pertaining to the probe during an unrelated investigation of her top staffer’s estranged husband former Congressman Anthony Weiner.