(Gallup) PRINCETON, NJ — The latest Gallup Poll Daily tracking finds Barack Obama moving to an eight percentage point lead over John McCain, 49% to 41%.

Obama’s significant lead over McCain almost certainly reflects the effects of the Democratic National Convention. The two presidential candidates were tied at 45% in the last Gallup Poll Daily tracking results conducted entirely before the convention began. The latest results include interviews from Tuesday through Thursday night, though most of the interviewing was conducted before Obama’s acceptance speech late Thursday.

Gallup has measured the convention bounce for candidates in previous years by comparing the last poll conducted entirely before the convention began with the first poll conducted entirely after the convention concludes. That historical calculation is complicated this year by the intense media focus on McCain’s selection of Alaska Gov. Sarah Palin as his vice presidential running mate on Friday, and the increasing focus on next week’s Republican National Convention.

Obama has clearly seen a rise in the polls since the convention began with a 4-point increase in his support (from 45% to 49%) with the margin moving eight points in his favor. Obama’s largest advantage at any point in the campaign was a 9-point lead recorded July 24-26, so as his party’s convention concludes, he is about as strongly positioned as he has been at any point this year. (To view the complete trend since March 7, 2008, click here.) — Jeff Jones