I was over at Pollster earlier this evening (part of my daily fix, which includes Real Clear Politics, Five Thirty-Eight, and Electoral-Vote) and I noticed something very interesting on the tracker of national polls. In national polls over the last several weeks (dating back to approximately mid-June) John McCain has never broken 44 % in a single national poll.
Except for Rasmussen.
Over the past several weeks, Rasmussen is the only national poll where McCain has broken 44%. Even the Gallup rolling poll, which has had McCain running closer to Obama then other national polls, has had McCain in the 43/44% range, while Rasmussen has had him consistently in the 46 or 47 range.
What is up with this poll, where McCain consistently outperforms every other national trend?
Just for kicks, I averaged out every national poll on Pollster from after the July 4 holiday to today, leaving out Rasmussen (and the since disproven Gallup-USA Today Poll, which has been proven to use rotten methodolgy). In those 28 polls, Obama holds a 3.3 % lead over McCain. Since the Rasmussen tracker shows McCain basically dead-even with Obama over that same period, it means that in a fairly large statistical universe, Obama has a fairly strong edge over McCain in all polls except for Rasmussen.
Please note that I am not doing this to denigrate the good folks at Rasmussen. I believe that their methodology is as valid as any until proven otherwise. I am curious, however, about what in their polling package causes the differences to occur. While the Gallup daily tracker shows Obama up by 3-4 %, and other one-day polling gives him a 5 -6% lead, Rasmussen is definitely an outlier of some sort, and I wonder if anyone has any insights as to what is causing this.
In the meantime, however, it seems to me that the Rasmussen poll might be solely responsible for the slight tightening in polls that we have seen since after Obama's trip. Since Rasmussen comes out every three days, it accounts for roughly a quarter of all national polls in any given period. Wipe out those consistent 46 and 47 % marks for McCain, and you have him trailing as much as ever.
Of course, they could know something that the rest of us do not.