When he was president, Jimmy Carter complained that the government's complicated personnel system made it darn near impossible to discipline or fire an "incompetent" civil servant.

He said, in effect, that because of all the insulation and red tape of the system, supervisors only rarely canned those who deserved it.

Other presidents had made the same complaint. But Carter did something about it. The "something" is the Civil Service Reform Act of 1978.

The act made a lot of big changes in government organization and personnel practices. Some of the most important of those changes are just now coming into play for rank-and-file workers. Tough new rating rules already have been applied to executives and supervisors.

One of the big changes--as a growing number of feds will tell you--is the new emphasis on a no-nonsense performance appraisal system.

Although hard numbers are not available, spot checks with federal agencies, and calls from unhappy workers, indicate that the number of disciplinary actions, ranging from reprimands to demotion or dismissal, is on the rise.

The reform act requires agencies to take performance appraisals more seriously, and to take action if a worker gets two consecutive annual unsatisfactory ratings. Agencies were told that supervisors were to stop handing out satisfactory ratings to people who don't deserve them.

The increase in disciplinary actions is starting to hurt. For example, last week the Department of Health and Human Services fired one of its training officials, a military veteran with 29 years of service. Several other headquarters employes--one a Grade 15--have been demoted for getting bad performance ratings.

HHS says everything was done by the book. The unlucky employes were counseled, the department said, and action was taken only after they failed to shape up.

The American Federation of Government Employees is championing the cause of the fired veteran.

(AFGE represents many of the departments' headquarters workers, and is facing a challenge from the National Treasury Employees Union, which wants the job. Employes will vote for their favorite union in mid June.)

AFGE has organized informational picketing of HHS headquarters to call attention to the firing, which it says is political. AFGE says the man got fired because his bosses and the Reagan administration didn't like his work in programs aimed at helping minorities move up in government.

The union plans to fight the dismissal--which it contends has more procedural holes than a chunk of Swiss cheese. First stop is the Merit Systems Protection Board's office of special counsel.

Firings are usually a tough call. Figuring out who is "wrong" isn't easy. It may be weeks or months before the HHS case is settled.

But federal personnel officials say that one thing is sure. The performance appraisal system is law, and there will be more firings and demotions.

So when the boss calls you in to talk about establishing your job goals for the year, and the "critical elements" you will be rated on, listen very carefully. Your job depends on it.