Joe Sestak has spent the week trying to drum up support for a candidacy which Rasmussen said yesterday is trailing Pat Toomey by ten points. So Sestak has begun citing internal Democrat polling that shows him either tied or even leading slightly. Nate Silver at the New York Times dissects these polls:
Our forecast yesterday evening, which did not yet include the Rasmussen poll (nor the internal polls; we do not use them in our Senate predictions), showed a projected 7-point victory for Mr. Toomey and gave him a 92 percent chance of emerging as the victor. None of the new information would lead me to deviate greatly from that forecast.
I’m not sure why people take polls released by campaigns at face value. This does not mean that campaigns don’t have very good pollsters working for them. But the subset of polls which they release to the general public is another matter, and are almost always designed to drive media narrative. For an instructive example, Google the term “internal polls”: the first result is a blog post, circa late October 2008, entitled “McCain’s Internal Polls Looking VERY Good.” [emphasis added]
Meanwhile, Huffington Post pollster Mark Blumenthal put it this way:
“More data will clarify the Pennsylvania picture, but for now the three new polls narrow our standard trend estimate slightly, to a 6.4-point Toomey advantage (47.6 percent to 41.2 percent),” Blumenthal wrote. “With the two partisan polls excluded, Toomey’s lead would expand to about eight points (48.3 percent to 40.1 percent).”
Or, as a Toomey spokeswoman put it earlier this week:
“You can believe the last 16 different independent polls that show Toomey ahead, or you can believe one Democratic Party poll that shows Sestak ahead,” a campaign spokeswoman said.
So is Joe Sestak gaining momentum? Is the race tightening?