Treasury Secretry Donald T. Regan is the valedictorian of the freshmen Cabinet class of 1984, according to a U.S. News & World Report survey.

The Cabinet's "grades" came from 131 Washington "insiders," selected by the magazine for their familiarity with President Reagan's administration, who evaluated the Cabinet members' effectiveness, competence and leadership abilities.

Regan, who got an 8.8 on a scale of 10, was described as "a deft and dynamic salesman of the Reagan economic package" who has avoided the "image problems that have plagued more experienced leaders like [Secretary of State Alexander M.] Haig."

Secretary Drew Lewis of Transportaton came in second with a score of 8.3, Caspar W. Weinberger of Defense with 7.5, Haig with 7.3, Terrel H. Bell of Education with 7.0, Malcolm Baldrige of Commerce with 6.7, James G. Watt of Interior with 6.6, and John R. Block of Agriculture with 6.4.

On the lower end of the curve were Attorney General William French Smith with a 5.4 rating, Richard S. Schweiker of Health and Human Services with a 5.1, and Samuel Pierce of Housing and Urban Development with a 4.9. Vying for last place were James B. Edwards of Energy, with a 4.4, and Raymond J. Donovan of Labor, with a 4.3. The two, the magazine said, "are seen as still struggling to master their departments."

According to the insiders, who ranged from presidential aides and members of Congress to committee staffers and lobbyists, the class average was 6.4 -- not great, maybe, but significantly better than the 5.8 rating earned by the Carter Cabinet in 1978.

The rating reflects grudging admiration for Reagan's selections, even among those who disagree with them, the magazine said. And a Democratic committee staffer agreed: "We're not taling about policy but about leadership. It's amazing how people so talented can be so wrong on the issues."