The 150,000 government workers under merit pay can expect raises ranging from 2 percent to 9.8 percent this fall, while their subordinates get a flat 4 percent October increase.

In the Washington area an estimated 60,000 supervisors and managers -- in grades 13, 14 and 15 -- are in the controversial carrot-and-stick pay system created by the Carter administration.

Last year, the first time merit pay was implemented, rank-and-file white-collar government workers got a flat 4.8 percent raise. Supervisors and managers under merit pay got between 4.8 percent and 7 percent.

The merit pay law guarantees supervisors and managers only half of the regular percentage pay other employes get each October.

Last year, because of a last-minute dispute between Office of Personnel Management and the General Accounting Office over the amount of money available for merit raises (OPM wanted more, GAO cut the amount back), OPM Director Donald Devine set the base merit raise at 4.8 percent. Result was that even those with less-than-satisfactory ratings got a 4.8 percent raise.

This year, agencies will give those with marginal or unsatisfactory ratings only 2 percent -- half of the regular federal pay raise.

Although there are 90 different merit pay systems in use -- agencies can do their own thing within OPM guidelines -- most use a five-grade system, with the top rating "outstanding," then "exceeds satisfactory," then "satisfactory," "marginally satisfactory" and "unsatisfactory."

Following is a comparison of how merit pay worked last year, and how it will work this year. Remember the regular 1981 federal pay raise was 4.8 percent, while this year the general increase for rank-and-file workers (who are not under merit pay) will be 4 percent.

1981: Merit pay managers who received top or outstanding ratings got between 6.4 percent and 7 percent, according to data compiled by the OPM. Those who got "exceeds satisfactory" or equivalent ratings got between 6 percent and 6.25 percent. Those with "satisfactory" ratings in 1981 got between 5.5 percent and 5.8 percent and those rated the equivalent of "marginally satisfactory" or "unsatisfactory" got 4.8 percent.

1982: This year, OPM expects agencies to give top merit pay performers raises of between 8 percent and 9.8 percent, at least double the regular October raise for rank-and-filers.

Merit pay workers who get the second highest rating should get anywhere from 6.4 percent to 7.8 percent according to the OPM model, which will vary from agency to agency. A "satisfactory" rating should be worth between 5 percent and 5.9 percent. Those rated as marginal and/or unsatisfactory will get only 2 percent, half the regular rank-and-file raise. .

Actual payouts will depend on the grades given people in each merit pay group. If, for example, a large number of managers/supervisors get high ratings, the individual payouts for them will be smaller. Agencies that rate a large number of people satisfactory or below, will have more money to give larger percentage increases to the relatively few who get top marks.

September and October are the rating periods for most of the supervisors/managers. Their performance appraisals will determine their standing within their peer group and how much, or how little, they get as a merit raise.

Many people under merit pay think the system is unfair because it does not allow managers/supervisors to get longevity (in-grade) pay raises that other workers get more or less automatically. In-grades, worth three percent, come due annually -- every other year or every third year, depending on time in grade.

Because of the regular in-grades, which 98 percent of the eligibles get, many workers this year will get or have gotten a 3 percent in-grade and will also get the 4 percent October adjustment.