Cross-posted at Immizen.com
A rather dramatic divergence has occurred during the Democratic National Convention between the two major election tracking polls, Gallup and Rasmussen. Halfway through the convention the Rassmussen poll started tilting sharply negative toward Obama, but the Gallup poll showed the President's favorability numbers improving. Today, the day after Obama's speech, the Rasmussen poll has Obama at 46% approve and 54% disapprove, but the Gallup tracking poll has Obama up 52% approve to 43% disapprove. Besides the huge 17% difference itself, what could account for the diametrically opposed trends?
The simple answer is these two polls really are talking to different groups of people. Gallup includes people regardless of phone type, including cell phones, but Rasmussen restricts itself to landlines only. Polls that have released cross-tabs showing the difference in reponse betweens the two groups of users, have shown that cell phone only users are, not surprisingly, younger, more liberal and more likely to support the Democratic Party. People that are landline only are, in a word, old.
After Romney picked Paul Ryan to be his running mate, the Rasmussen poll was decidedly unaffected. In fact, the Romney Rasmussen numbers actually dipped for a week or so. This is not surprising if you think of Rasmussen poll respondents as mostly old people who are not entirely thrilled by the guy who wants to turn Medicare into a voucher system. Even so, this group did not feel the love going around at the DNC and let the Rasmussen robo-pollers know it. Gallup poll respondents, them with the new-fangled Android and iPhone thingies, defintely got the Obama message.