“One guiding principle that we employ is, ‘look at the data,’ ” said Michael Schaal, director of the Office of Petroleum, Natural Gas and Biofuels Analysis within the Energy Information Administration. “It is clear the data shows that shale gas has become a significant source of domestic natural gas supply.”

But the doubts and concerns expressed in the e-mails and correspondence obtained by The Times are noteworthy because they are shared by many employees, some of them in senior roles. The documents and e-mails, which were provided to The Times by industry consultants, federal energy officials and Congressional researchers, show skepticism about shale gas economics, sometimes even from senior agency officials.

The e-mails were provided by several people to The Times under the condition that the names of those sending and receiving them would not be used.

Some of the e-mails suggest frustrations among the staff members in their attempt to push for a more accurate discussion of shale gas. One federal analyst, describing an Energy Information Administration publication on shale gas, complained that the administration shared the industry’s optimism. “It seems that science is pointing in one direction and industry PR is pointing in another,” wrote the analyst about shale gas drilling in an e-mail. “We still have to present the middle, even if the middle neglects to point out the strengths of scientific evidence over PR.”

The Energy Information Administration, with its mission of providing “independent and impartial energy information to promote sound policymaking” and “efficient markets,” was created in response to the energy crisis of the 1970s because lawmakers believed that sound data could help the country avoid similar crises in the future.

As a protection from industry or political pressure, the Energy Information Administration’s reports, by law, are supposed to be independent and do not require approval by any other arm of government.

Its administrator, Richard G. Newell, who announced this month his plans to resign to take a job at Duke University, has hailed the prospects for shale gas, calling it a “game changer” in the United States energy mix. “The energy outlook for natural gas has changed dramatically over the past several years,” Mr. Newell told the Natural Gas Roundtable, a nonprofit group tied to the American Gas Association. “The most significant story is the transformative role played by shale gas.”