Big pay changes on the drawing board.

Thousands of nonsupervisory feds in professioal and clerical jobs would lose guaranteed annual raises under a system Uncle Sam will test. It links all pay hikes to performance and productivity.

New modified merit pay plans being developed would eliminate grades for persons in GS 1 through 15. They would lose the right to automatic longevity (in-grade) raises. The size of the regular October annual adjustment would be based on merit, as determined by immediate bosses.

Authority for the merit pay tests stems from President Carter's civil service reform. It allows government to test merit pay models on up to 50,000 of Uncle Sam's 1 million white-collar workers.

Most federal workers would continue to get the full amount of the October raises. They are supposed to represent a catch-up with industry.

Employes put in merit pay test programs would not automatically get the same raises as their colleagues. They would have to be rated satisfactory" by bosses to get the full October raise.

Those who get poor marks would get less, or nothing. In addition bosses (who would be under an even tougher "merit pay" system) would be told to be tougher in rating employer' work habits. Ninety-nine of every 100 workers now routinely gets a "satisfactory" mark.

Workers in merit pay test programs could also get larger-than-normal raises, if bosses rated them as outstanding.

Everybody put under merit pay test programs would lose the right to regular longevity (in-grade) raises. They are worth 3 percent, and come due every one, two or three years -- depending on an employe's time in grade.

Money "saved" by eliminating the regular in-grades for the test group would be used to finance higher indreases each October for "outstanding" workers.

The merit pay system is years away for most federal workers. However, two of Uncle Sam's biggest operations -- the Navy Department and Department of Health and Human Services (formerly HEW) -- have merit pay test programs in the works.

Navy's nonsupervisory merit pay plan will be tested on a group of civillians in California. It has been okayed by the Office of Personnel Management. OPM must clear all federal pay test projects.

Health and Human Services' proposal would cover 3,200 workers in the Center for Disease Control. Most are based in Atlanta.

Other agencies are studying merit pay test systems that they will introduce to limited groups of workers. If the system proves successful -- and Carter's reform plan envisions that merit pay should replace automatic raises -- it is only a matter of time before it is government-wide.

OPM brass are studying the HHS modified merit pay system. Congress also would have to okay it since the modified merit pay concept represents a sharp departure from regular civil service salary regulations.

In the CDC proposal, clerical and technical workers would be lumped into "pay ranges" covering two grades. Grade 5 and 6 personnel, for instance, would go into a pay range of $11,243 to $16,293. GS 11 and 12 would be given a range of $20.611 to $31,110. Workers would come in at their current salaries, but could move anywhere within that range under the modified merit pay system.

Administrative and professional personnel, in the CDC model, would go into ranges covering two or three grades. Grades 5 and 8 would have a range of $11,243 to $20,049. Grades 9 through 11 would become pay range $17,035 to $26,794. The GS 12 and 13 range would go from $24,703 to $38,186.

Officials stress that the CDC program is still a proposal, and that merit pay for all government workers is a long way from reality. But the handwriting is on the wall for everbody in government to read and ponder.