Yeah, unfortunately, I just don’t think D+6 is realistic in a state with a D+13 registration advantage (D+12 active reg advantage as of 10/15/2012.) D+8 or D+9 is probably closer to reality. That still makes it VERY CLOSE.
Regardless of the D registration advantage, the self-identified vote went D+7 in 2008 and D+2 in 2004. a D+6 sample may be OVERSAMPLING Democrats.
Actually, D+6 is quite reasonable. If anything, it understates the crossover vote this year. A D+4 or D+5 is more likely, IMO.
In Pennsylvania, voter registration is a lousy indicator of voter intent. Consider the fact that a D+13 registration advantage has resulted in a current Republican Governor, Republican control of the General Assembly, a Republican majority Congressional delegation, and one of the most conservative Republican US Senators(Pat Toomey).