A new national poll indicates that Mitt Romney's announcement of House Budget Chairman Paul Ryan as his running mate has not made an immediate impact on the race for the White House.

According to Gallup, 47% of registered voters supported Romney and 45% supported President Barack Obama in the four days of their daily tracking poll following Romney's Saturday morning announcement that the seven-term congressman from Wisconsin would be his running mate on the Republican ticket.

That's little changed from the four days before the August 11 announcement, when numbers from the Gallup Daily Tracking poll indicated 46% of registered voters saying they would back Romney and 45% saying they supported the president. The slight change is well within the survey's sampling error.

Will the Republican ticket enjoy a delayed bounce?

"While the initial indication is no increase in Romney's support after naming Ryan, the data suggest the possibility that Romney may get a delayed bounce, as he fared slightly better in Aug. 13-14 Gallup tracking than in Aug. 11-12 tracking," says the release from Gallup.

Neither Gallup polling or CNN/ORC polling found any real change in the race for the White House immediately after the naming of Sen. Joe Biden of Delaware and Alaska Gov. Sarah Palin as the running mates in the 2008 campaign. But polling did indicate that the vice presidential choices had a bigger impact in the 1996, 2000 and 2004 elections.

The Gallup Daily Tracking Poll was conducted August 7-14, with 1,863 registered voters questioned by telephone. The survey's overall sampling error is plus or minus three percentage points.