A new USA Today/Pew Research poll is out with a generic ballot question. It has the Democrats leading by 4 points, in what appears to be a major reversal from other polls showing a big Republican lead. So is this a bounce back for Democrats and a showing that the big Republican wave won't happen?
No, it isn't. A Republican wave is hardly inevitable, but this doesn't tell us much. First, this poll was also taken at the same time as Rasmussen, McClatchy/Marist, and Quinnipiac, all of which are E to R+5. So there's no indication that Democrats are ahead with other pollsters.
Every pollster has their own methodology and their own sample. The Pew poll's methodology might favor Democrats or their sample could be more Democratic than others. A better way to look at a pollster's data is to look at their trend line and see how this survey compares to previous ones.
Unfortunately, this is only the second time this year Pew/USA Today has done the generic ballot. They did it in October, at the height of the government shutdown. Democrats were D+6 then and D+4 now. That's not unexpected because that was a good period for Democratic candidates. A November poll, during the Obamacare meltdown, would provide us with more information, but we don't have that.
So this is a good poll for Democrats, but we shouldn't read much into it. The election is still 11 months away. A lot will change between now and then.