President Barack Obama gained a six percentage-point advantage over Mitt Romney among registered voters following the Democratic National Convention, according to a poll that also finds a virtual tie among those most likely to vote.

The president’s position in a match-up with the Republican nominee among all registered voters is his strongest since April in an ABC News/Washington Post poll, which found 50 percent supporting Obama and 44 percent backing Romney in the three days after the Democrats’ nominating convention in Charlotte, North Carolina.

A CNN survey conducted during the same three days found Obama holding a 52 percent to 46 percent advantage over Romney among likely voters. A CNN survey taken Aug. 31-Sept. 3, following the Republican National Convention in Tampa, Florida, had found the two men tied at 48 percent.

The post-convention findings are similar to what the Gallup Poll showed in its daily tracking of the presidential contest, with the latest seven-day average of surveys covering the period of the Democratic convention and two days afterward --Sept. 3-9 -- showing a 49 percent to 44 percent advantage for Obama among registered voters. Gallup’s seven-day survey of 3,050 voters has a margin of error of plus or minus two percentage points.

Neil Newhouse, pollster for the Romney campaign, yesterday dismissed the post-convention gain for Obama as “a bit of a sugar high.”

“The reality of the Obama economy will reassert itself as the ultimate downfall of the Obama presidency,” he said.

Gender Gap

Still, the CNN survey of likely voters found a narrowing gap among men, who tended to support Romney in pre-convention polling. Obama led Romney, 48 percent to 47 percent, among men in the CNN poll and continued to hold an advantage among women, 55 percent to 44 percent.

The latest polls reveal what pollsters call a “bounce” for the president from the nominating convention.

The ABC/Post poll’s six percentage-point advantage for Obama among registered voters compares with a one-point advantage for Romney -- 47 percent to 46 percent for Obama -- in a survey taken immediately before the conventions. The post- convention findings mark Obama’s best standing since April in the survey, conducted by Langer Research Associates.

Obama’s job approval as president stood at 48 percent in the latest survey, and among those considered most likely to vote in the ABC/Post poll, Obama drew the support of 49 percent and Romney 48 percent -- statistically unchanged from pre- convention findings.

Biggest Shift

Langer Associates said the biggest shift has been among Democrats coalescing around their party’s nominee. Obama’s support among Democrats registered to vote has advanced by eight percentage points, to 91 percent, following the convention.

In the eight states that Obama and Romney are contesting most heavily -- which include Ohio and Florida -- the ABC/Post poll found a 54-40 percent advantage for the president, compared with a 42-48 percent deficit for Obama before the convention.

Sixty-three percent of the registered voters surveyed say Romney hasn’t provided enough details about the policies he would pursue as president, compared with 31 percent who say he has.

Economic Issues

While 53 percent of registered voters disapprove of Obama’s handling of the economy, and 43 percent say the economy has gotten worse under his presidency, 57 percent say it wouldn’t have done any better under Romney.

By 10 percentage points -- 50 percent to 40 percent -- most surveyed say the president better understands economic problems people are having, and a wide margin -- 61 percent of those polled -- rate the president as more personally likeable, while 27 percent preferred Romney.

Obama is viewed as a stronger leader by 50 percent, compared with 42 percent for Romney, and as better able to work with both sides of Congress by 46 percent, compared with 41 percent for Romney.

The ABC/Washington Post Sept. 7-9 survey of 826 registered voters has a margin of error of plus or minus four percentage points. The Sept. 7-9 CNN/ORC international poll of 709 likely voters has a margin of error of plus or minus 3.5 percentage points.

Convention Highlights

Separately, a poll released yesterday by the Pew Research Center found former President Bill Clinton’s address was the highlight of the Democratic National Convention, overshadowing Obama’s speech accepting the presidential nomination.

Pew reported that 29 percent of adults who watched the convention identified Clinton’s address as the highlight, compared with 16 percent who picked Obama’s speech and 15 percent who cited first lady Michelle Obama’s remarks to the delegates.

A Pew poll last week found that the highlight of the Republican convention was actor Clint Eastwood’s “dialogue” with an empty chair, followed by Romney’s acceptance speech.

Obama’s acceptance speech was viewed favorably by 60 percent by those who watched it compared with 53 percent of those who tuned in to see Romney, according to the Pew poll.

Obama’s speech reached more people; 43 percent said they watched some or all of the Democratic convention last week, compared with 38 percent who saw some or all of the Republican gathering. Four years ago, 46 percent of adults watched all or some of the Democratic convention and 56 percent saw all or some of the Republican event.

Both nominees received boosts from the convention, with 25 percent saying their opinion of Romney was more favorable following the Republican gathering and 26 percent saying their opinion of Obama was more favorable after the Democratic convention.

Pew’s survey of 1,012 adults was conducted Sept. 7-9, and had a margin of error of plus or minus 3.6 percentage points.

To contact the reporter on this story: Jonathan D. Salant in Washington at jsalant@bloomberg.net

To contact the editor responsible for this story: Jeanne Cummings at jcummings21@bloomberg.net