Candidate Jimmy Carter campaigned against big government and against the evils of government secrecy.

It was effective, Secrecy, for many Americans, was a code word for Richard M. Nixon, and those who abhorred Watergate cheered Carter's promise to "strip away all the secrecy that surrounds government . . ."

President Carter has had a month in which to start that stripping away, and evaluations of his administration's performance are mixed.

Carter has fulfilled his promise to be regularly available to reporters, and he has introduced his version of the fireside chat and his visits to government departments where he takes questions from civil servants.

White House press secretary Jody Powell, whose job makes him the czar of openness, says he and Carter are generally pleased with the administration's performance.

"We've kind of got something here that we've always said we wanted," Powell said in an interview. The White House staff "all know that I'm not going to get upset with them about talking to the press without me knowing about it."

Some White House staffers, however, still respond to questions by asking whether the reporter has checked with Powell.

For reporters who cover the White House, openness means access to the key officials, and several of them are inaccessible. Hamilton Jordan's secretary tells most would-be interviewers they will have to wait several weeks to talk to the presidential assistant.

Powell himself is swamped with phone calls and visitors.If a newcomer has an appointment with Powell, reporters and White House press aides routinely advise: "Bring lots to read." The wait can be several hours.

Powell said that the demands on his time are a little heavier than he had imagined, but that much of what he is doing is the kind of one-time greeting that he hopes will drop away, leaving him freer in the future.

"People want to come by and say 'hello' and I hate not to see people," Powell said. As a result, some days he doesn't return all reporters' phone calls.

At the other extreme, Carter has startled at least one reporter by personally telephoning to answer a question put to him through the White House press office.

Carter set extraordinary goals for his administration, and some of them have proved unworkable. Last week, for example, his idea that Cabinet meetings might be opened to the press was scrapped. Cabinet members objected that opening the sessions would result in "subterfuge," in which sensitive matters would be discussed in separate, private meetings.

Powell holds a weekly meeting with public information officials of the government departments. They have been briefed on the requirements of the Freedom of Information Act and also have been instructed on the virtues of openness, which Powell says are partly a matter of principle, but are also practical consideration.

"The fact is that it's pretty difficult to keep a secret anyway around here," he said. "And I've always believed the old saying that bad news never gets better with age. Generally you'd better off getting it out and getting it over with."

In Cabinet agencies, the impact of Carters openness doctrine has been felt unevenly.

At the State Department, officials giving the daily briefing have been more forthcoming in response to questions and have volunteered some information.

Access to officials, however, has gone down. One reason is that none of the top-level people who require Senate approval has yet been confirmed except Secretary of State Cyrus R. Vance, and several have told reporters they are reluctant to talk while still facing a Senate hearing.

They also are extremely busy.

Vance has given several interviews and a press conference, and promises at least one press conference every month.

He also said Jan. 31 that he believes "it is necessary to inform the American public as to what our objectives are, to explain why we hold these objectives, and as much as possible to explain how we intend to proceed in achieving them."

James R. Schlesinger, the White House energy coordinator, has been almost impossible for reporters to see, while the director of the Federal Energy Administration, John F. O'Leary, has been available.

Both of them have been busy with the natural gas crisis, which provided an early test of Carter administration intentions. In general, reporters say that the government gets good grades for its willingness to candidly discuss the day-to-day natural gas situation. The commissioners and staff of the Federal Power Commission were available to answer press calls.

On the other hand, Interior Secretary Cecil D. Andrus, who took up his post promising a move away from the secrecy that surrounds oil and gas matters, last week stamped secret a report on whether gas producers withheld supplies. He released the report two days later, after requests from Congress and the press.

A firm believer in Carter's openness is his fellow Georgian, Bert Lance, director of the Office of Management and Budget. Often Lance picks up his phone himself, and one reporter says he's talked more to Lance in the last two weeks than to predecessor James T. Lynn in two years.

Not only is Lance accessible, reporters say, he is forthright and helpful.

The new Treasury Secretary, Michael Blumenthal, also gets good grades from reporters, as do many of his assistants, although some share their State Department counterparts' fears of talking too freely while still awaiting confirmation.

At the Pentagon, little appears to have changed, but Defense Secretary Harold Brown is beginning to make a serious and continuing effort to meet with the press.

Brown reportedly was displeased by the leak of his proposed $2.8 billion budget cuts; in reaction, some Pentagon offices put a tight lid on information.

However, much of the tightness at the Pentagon is attributable to the newness of the administration, reporters think.

When the administration wanted reporters to see the fly on the "Doomsday" command plane Carter planned to take to Georgia for a weekend, initial Air Force objections that the entire plane was secret was overcome.

Not only did reporters fly with Carter, but the Air Force arranged for a press look at the plane before hand.

In every department, and in the White House, it appears too early to tell how Carter's promises of openness will be carried out.

"We've never been here before," Powell remarked. "Everybody's in a process of adjustment."