Another data point to add to the cluster of post-convention polls: Gallup gives President Obama a three-point convention bounce and a six-point lead over Mitt Romney in a survey of registered voters. 

Obama and Romney were deadlocked at 47 percent to 46 percent in Gallup's last poll before the convention; Obama now leads 50 percent to Romney's 44 percent. Obama's approval rating has also increased from 45 percent to 50 percent.

That's consistent with the Post-ABC News poll released today, which gave Obama a six-point lead with registered voters, but no bump with likely voters. 

Democrats consistently perform better in polls of registered voters over polls of likely voters. Based on the past three elections, however,Gallup's Jeffrey M. Jones writes that only two to four points should be added to Romney's numbers to account for differences between their polling and turnout.