I believe Gallup has it 47 for Obama to 46 for Romney. Rasmussen has it 47 for Romney to 44 for Obama. I believe the Gallup poll is a 7 day moving average. Rasmussen is a 3 day moving average. I believe Gallup uses 3500 registered voters; Rasmussen uses 1500 likely voters. Obviously, Rasmussen is more likely to be more accurate given the differences between the methods. There may be other factors that make Rasmussen more accurate, but those are the main ones.
“I believe Gallup has it 47 for Obama to 46 for Romney. Rasmussen has it 47 for Romney to 44 for Obama.”
I think Rasmussen said he just counts likely voters.