This change is well within the margin of error of both polls. It could be statistical noise. It could really be a 6-point move in McBride's favor. It could be that the previous poll was wrong. There's really no way to know. All that we can say with reasonable certainty, is that statisically this race lies somewhere between 53-39 Bush and 47-45 McBride. That's not real helpful of course! But considering that Zogby had this race at 49-39 on Monday, and that Bush was up 12 just before the primary, I think it's pretty likely that Bush's real lead is around 8-9 points.