Evan Vucci/AP

Another national poll shows neck-and-neck race

The president leads his challenger by a hair in latest CBS News survey.

Yet another poll confirms that the presidential race remained a virtual tie headed into each party's convention, with a new CBS News survey released Tuesday showing the two candidates separated by an insignificant, razor-thin margin.

The poll, conducted Aug. 22-26, shows the incumbent ticket of President Obama and Vice President Joe Biden leading the presumptive Republican nominees, Mitt Romney and Rep. Paul Ryan, 46 percent to 45 percent. Four percent of registered voters say they won't vote or prefer another candidate, while another 6 percent are undecided.

Each ticket wins about 9-in-10 of their own partisans, while self-identified independent voters are split, 41 percent for Romney to 40 percent for Obama.

The poll shows a significant gender gap: Male voters favor Romney, 49 percent to 41 percent, while female voters prefer Obama, 51 percent to 41 percent.

Each candidate has a net-negative favorability rating in the poll (CBS News offers two undecided options to respondents, often leading to lower favorable and unfavorable percentages than other surveys), according to partial results released by CBS News. And, while Obama is seen by more voters as understanding the problems of people like them, more voters say Romney has a clear plan for creating jobs.

The poll surveyed 1,051 registered voters and carries a margin of error of plus-or-minus 3 percentage points.