The percentage of voters believing that the country is better off since Barack Obama became president jumped seven points after the two political conventions, according to a new NBC News/Wall Street Journal poll.

Thirty-eight percent of registered voters now say the nation is better off, which is up from 31 percent in the August NBC/WSJ poll conducted before the conventions.

Still, a plurality of voters -- 41 percent -- believe the country is worse off, while 21 percent think it's in the same place.

"Are you better off than you were four years ago?" has been a question that Republicans raised right before the Democratic convention began earlier this month. And top officials and surrogates from the Obama campaign had a difficult time, initially, answering the question.

The release of a surreptitiously taped Romney fundraiser yesterday added to a tough few weeks for Mitt Romney that included Clint Eastwood's appearance at the RNC and President Obama's post-convention bump in the polls. As NBC's Mark Murray and Domenico Montanaro discuss, with 49 days until Election Day, Romney's destiny may be out of his control.

But in his convention address the day before Obama's acceptance speech, former President Bill Clinton answered the question affirmatively. “No president -- not me or any of my predecessors -- could have repaired all the damage in just four years. But conditions are improving, and if you'll renew the president's contract you will feel it.”

And the Obama campaign followed up with a new TV ad -- on the fourth anniversary of Lehman Brothers' collapse -- also making the case that the country is better off.

The new NBC/WSJ poll asks a separate question: Which candidate -- Obama or Mitt Romney -- is better prepared to lead the country four years from now? On this question, 47 percent of voters pick the president, while 36 percent choose Romney.

The full NBC/WSJ poll -- which was taken of 900 registered voters (270 by cell phone) from Sept. 12-16 and which has an overall margin of error of plus-minus 3.3 percentage points -- will be released at 6:30 pm ET.

That release will include the poll's initial look at the presidential contest among likely voters.