The biggest disappointment in Jimmy Carter's Cabinet is Brock Adams, the Secretary of Transportation.

That's the consensus of White House men who sit in on Cabinet meetings and are deeply involved in administration policymaking. They say Adams is dragging his feet on key presidential policies in his area, such as airline deregulation. Besides that, says one of the President's men, the Transportation Secretary's "obsequious" manner grates on Carter.

The strongest Cabinet members are Energy Secretary James Schlesinger - after Bert Lance, the closest to a president confidant in the Cabinet - and Defense Secretary Harold Brown. "The nicest by far" is Interior Secretary Cecil Andrus. The most irascible is Housing and Urban Development Secretary Patricia Harris, who once dressed down a budget official while the President and the rest of the Cabinet looked on. Attorney General Griffin Bell tells the best jokes, and the most improbable success is Health, Education and Welfare Secretary Joseph Califano, who enrages Carter aides but somehow manages to please the President.

These are arbitrary judgements, of course. Yet they offer insights into the White House view of how one of Jimmy Carter's grand experiments - "Cabinet administration of our government" - is working out.

The answer, suggests one White House policymaker, is "better than any of the cynics, including myself, thought it would, but probably not as well as the President thought."

That means it must be working fairly well, because Carter's expectations were very high. As he repeatedly promised during the campaign, policymaking in his White House would be far different that in Richard Nixon's White House, where a powerful presidential staff dictated to a mostly docile Cabinet. Carter would make the big decisions - he left no doubt about that - but his staff would be small and keep a low profile. Many policy ideas would come from the Cabinet itself, and once the President had set policy, the Cabinet would execute it vigorously.

That was the theory, at any rate, and as events soon showed, the president was deadly earnest about translating theory into practice.

Like a schoolmaster handing out homework, he directed his Cabinet Secretaries to give him, every Friday, typewritten summaries of what they are doing. Carter reviews the summaries over the weekend, scribbling terse comments in the margin ("Expedite," "Proceed." "Is this right?"), and by nine o'clock Monday morning, when the Cabinet files into the sunny Cabinet Room overlooking the Rose Garden, he is ready to bore in with detailed questions.

But the Cabinet Secretaries, who sit around a long, battleship-shaped table, aren't equal in ability, nor are they equally cooperative in carrying out the President's wishes. ("He can send some of them memos - memos in his own handwriting, even - and they still come to us and say, 'He didn't really mean that,'" gripes a White House man.) Fairly or unfairly, here is how they appear in the eyes of the White House staff.

Michael Blumenthal, Treasury: Carterites apparently hoped the ex-Bendix Corp. chairman would be their counterpart to Gerald Ford's William Simon, a highly visible bridge to the business community. In this he's been "a disappointment," says one, and "not forceful enough" in the view of another. Yet he's described as a man who "doesn't wilt" in private policy debates with the President.

Joseph Califano, HEW: The dynamics of the Califano-Carter relationship are the most intriguing in the Cabinet. Right off the bat, Califano strained relations with the White House by hiring a Republican to a major post, which caught political aides by surprise and left them sputtering. But califano has turned out a prodigious amount of work - a welfare-reform plan, a departmental reorganization and a proposal to shoe up the Social Security system. And to the President, who likes deadlines and people who meet them, this outweights everything else.

Griffin Bell, Attorney General: "Well, he's not Robert Kennedy," says one Carterite. Not particularly vigorous, the ex-judge from Georgia comes across as "different from all the rest," a man who sometimes appears to be living in his own little world, another White House man observes. But Bell is completely at ease with his old friend the President, and sometimes enlivens Cabinet meetings with droll observations. At one meeting, he remarked that an idea being discussed was the kind of thing that works in practice but not in theory.

Cecil Andrus, Interior: Everybody's nominee for the Cabinet's nicest person. "Very smooth, adroit, extraordinarily pleasant and unassuming," says one White House staffer. Observes another: "He's the only one who may actually leave Washington when all this is over and - this is most unusual for a Cabinet officer - be actually tries to carry out the President's policies."

Patricia Harris, Housing and Urban Development: a wuick learner - with a lot to learn. "She rattles on and doesn't seem to know anything in Cabinet meetings," says one presidential staffer. Harris is credited with assembling an excellent staff. But she sometimes bores Cabinet members by dwelling on minor matters and repeating herself at Cabinet meetings.

Bob Bergland, Agriculture: Another low-key, unassuming, affable type - but not quite as popular with White House staffers as Andrus is. That's because Bergland got caught in the middle of a Jimmy Carter vs. Congress fight over how much to spend on the new farm bill. He helped engineer a compromise and, as is often the fate with compromisers, pleased neither side.

Ray Marshall, Labor: He is credited with being on top of his department and in the good graces of his number one constituent, George Meany. But Marshall wears his liberalism on his sleeve, which handicaps him with the moderately conservative Carterites. Besides, he talks too much at Cabinet meetings, staffers say.

Harold Brown, Defense: "Very bright and very good," is a typical assessment. An intellectual dreadnought, capable of overwhelming most of his Cabinet colleagues in any test of logic, he's also shrewd enough to avoid trying to overwhelm Carter. Thus, although an advocate of the B-1 bomber before taking office, he could support the President's decision to kill it without any outward sign of pain.

Cyrus Vance, State: The benign, unflappable Vance has had a run of bad luck lately, notably a Middle East trip that failed to live up to advance expectations. But White House men say he still has the full confidence of the President. Before the Secretary's recent trip to China the White House did make one tactical adjustment, though: a deliberate effort to dampen public and press expectations, and thus avoid a repetition of the Middle East experience.

Juanita Kreps, Commerce: Although bright and articulate, she's yet to rise above the limitations of her chronically weak department. But she is perceived as trying, and already has collided with Harris over who has jurisdiction over urban economic development. And the President's government reorganizers say she's prepared to capitalize upon the reorganization process by absorbing castoffs from other departments.

James schlesinger, Energy: Legend has it that one reason Gerald Ford fired Jim Schlesinger as Secretary of Defense was that Schlesinger never deigned to look at him during Cabinet meetings. Instead, he looked at Henry Kissinger, as if to imply that his remarks would be lost on the bumbling Ford. Carterites report that Schlesinger does look at Jimmy Carter. In fact, it's probably a mutual admiration society, because, of all the Cabinet members, he's temperamentally the most like the Presdient: hard-driving, impatient, a man who believes everyone would share his lofty goals if only they understood the logic of them as well as he does.

Nevertheless, Schlesinger sometimes goes out of his way to be deferential. "You're looking splendid today, sir," he informed Carter at one joint news briefing. Even in Jimmy Carter's "Cabinet administration," it's obvious that no one has forgotten who the head administrator is.