Just 20 percent of Americans have a positive view of federal agencies, according to a survey released this morning by Gallup.

The survey explored public perceptions of government; it asked respondents to identify the agencies they viewed as the most prestigious, the most important, and the best places to work. The Defense Department received some of the highest scores: 23 percent of respondents identified it as the most prestigious agency, with the CIA coming in second at 17 percent. The CIA was also ranked the best place to work.

Six in 10 Americans said their most recent interaction with the federal government was a positive one.

"When the public interacts with government, it often has no alternative, unlike its interactions with the private sector," said Bernadine Karunaratne, a partner at Gallup. "When the public interacts with a federal agency, it impacts not just how they feel about that agency, but how they feel about the federal government as a whole."

Frank Newport, the editor-in-chief for The Gallup Poll, said many citizens with negative impressions of government were frustrated by problems they had during past interactions with agencies. He said resolving citizens' problems was the best way to improve an agency's standing.

"Problem resolution is at the top of the list. ... Your rating of how well an agency resolved a problem was the No. 1 determinant of your rating of that agency," Newport said.

When asked which agencies have the biggest overall impact on their personal lives, respondents offered varied answers. The Social Security Administration scored highest in that category, at 11 percent; the Health and Human Services Department was second, at 10 percent.

The survey also asked respondents which agency they felt was "most important to the future." Defense received the highest score, 27 percent; the Education Department came in second, at 11 percent. The Agriculture Department was considered the least important, with just 2 percent of respondents choosing it.

Gallup also asked how Americans interact with the federal government. Forty-one percent said they interacted with government Web sites in the last six months; 40 percent said they had never interacted with a federal Web site.

Experts said the poll — the first of its kind — highlighted the need for government to do a better job explaining its mission to the public.

"Government doesn't market itself very well," said Patricia McGinnis, a professor at Georgetown University's Public Policy Institute. "I'm not suggesting that you stop doing your work for the public and focus on image, but put this in the background, use this as context, because government does need to do a better job of marketing itself, there's no question."

McGinnis acknowledged that agencies are often reluctant to spend money on advertising because of federal laws against propagandizing. But she pointed out that a few agencies — the Defense Department, in particular — spend money on advertising campaigns. Those agencies tended to fare better than most in Gallup's survey.

"People are too shy about coming close to the line. There are agencies that spend money on advertising. [The] CIA is one example," said Max Stier, the president of the nonprofit Partnership for Public Service. "The real problem is money. ... Very few agencies have the resources where they could actually sustain any real advertising campaign."

The survey found much higher favorability ratings for the military: Seventy-eight percent of Americans said they have positive views of the armed forces.

Gallup interviewed more than 41,000 people for the survey, which was conducted in May and June of this year.