The additional compensation to be paid to "teacher coordinators" in the Prince George's County schools will depend on the outcome of negotiations now under way with the teachers' union. Circumstances involving the additional pay were reported incorrectly yesterday.

More than a decade before President Reagan endorsed merit pay for teachers, the District of Columbia school board backed the same idea--and then didn't carry it out.

In 1970 psychologist Kenneth B. Clark, a professor at City University of New York, prepared a plan to upgrade Washington's public schools. One of its chief elements was ranks for teachers, similar to those of college professors and based partly on the gains students made on achievement exams. The higher ranked "master" teachers, Clark proposed, would be paid as much as school principals.

The Washington school board approved the plan by a 9-to-1 vote and proclaimed a "reading mobilization year." But the Washington Teachers Union, led then as now by William H. Simons, denounced it as "antiteacher." Many teachers refused to administer the exams with which the plan was supposed to begin.

After several weeks of turmoil and the threat of a strike, the board agreed that the first round of tests would not be used to evaluate teachers; the union said it would not try to stop the exams. Marion Barry, then the leader of Youth Pride Inc., served as mediator of the board-union negotiating sessions that produced what was billed as a compromise.

But the union remained adamant against the "differentiated pay" plan, boycotting a committee that was supposed to discuss it. A new superintendent, Hugh J. Scott, also was cool to the idea, and the school board never tried to implement it. The rest of the Clark plan was carried out fitfully and eventually dissolved, despite prodding from Clark, who gained prominence when his research was cited by the U.S. Supreme Court in its 1954 school desegregation decision.

Clark complained bitterly that his plan for Washington's schools had been "consigned to the dung heap," but his merit pay idea now seems very much alive--in the Washington area as well as across the country. Carrying it out, though, may prove difficult again and for the same reason as a decade ago: opposition by teachers.

Exactly what merit pay means is a matter of considerable dispute, and the plans for achieving it vary widely. All of them carry some element of paying for performance, in contrast to the current, almost universal system in American public schools of paying teachers on a single salary scale tied entirely to years of seniority and academic degrees.

"No state pays any teacher one penny more for doing a good job," said Tennessee Gov. Lamar Alexander, whose master teacher plan was blocked in the state legislature last spring after attacks by an affiliate of the National Education Association, the nation's largest teachers union.

"There should be equal pay for equal work," rejoins Janice A. Piccinini, president of the Maryland State Teachers Association, the NEA affiliate in Maryland. "There's no objective criteria for determining who is better than whom in teaching . We think only good teachers should be in the classroom."

President Reagan began promoting the merit pay idea after it was endorsed in late April by the National Commission on Excellence in Education, whose report decried the "rising tide of mediocrity" in the nation's schools.

However, for several years before that there had been signs of increasing interest in the idea. In recent months, with Reagan's backing, it has surged even more.

For example:

The contract signed in April 1982 between the D.C. school board and the teachers union provides that teachers must receive a better than satisfactory rating in order to get a pay raise after their sixth year on the job. Although the exact terms of the rating system are still under discussion, the requirement is scheduled to go into effect in the coming school year, affecting about 90 teachers who are beginning their seventh year on the job.

In contract negotiations two years ago former Montgomery superintendent Edward Andrews, a strong proponent of merit pay, proposed giving $1,000 bonuses for exceptional performance to up to 10 percent of the county's teachers. The plan was not accepted by the local NEA affiliate, but a similar system was agreed to by the administrators union. Just before he left office last month Andrews sent out the first bonus checks--$1,000 each to 43 administrators.

The Prince William County School Board, which employs about 2,100 teachers, voted in late 1981 that teachers must receive at least a satisfactory rating to get a pay raise. Faced with fierce opposition from the teachers union, however, the board backed down from a proposal to give higher pay to teachers rated outstanding. Superintendent Richard W. Johnson, however, said last week that this idea may be revived.

In Virginia, where there is no collective bargaining by public employes, the Alexandria School Board last year adopted a similar system of requiring a satisfactory performance rating before teachers can get a pay raise. It also began awarding bonuses of from $500 to $1,500 to administrators. In early July Superintendent Robert Peebles indicated that he soon would push for merit pay for teachers, saying that the traditional pay system "tends to protect incompetency."

The Prince George's school board last fall instituted a system of "teacher coordinators" in county high schools. Starting this fall, these teachers will teach half time and spend the rest of the day helping other teachers and working on curriculum. School board spokesman Brian Porter said they will receive slightly higher pay depending on the size of their departments.

Last October a commission established by the Maryland State Board of Education recommended ranks for teachers similar to those proposed by Clark. The plan received a strong endorsement from State Superintendent David Hornbeck.

When Piccinini and other teacher union leaders attacked the proposal as unfair and unworkable, commission chairman Stephen McNierney replied: "It's just mildly outrageous for people in a profession that specializes day after day in grading and evaluating students to say that teachers can't be graded and evaluated. Come on. They've got to be kidding."

Recently, Virginia Gov. Charles S. Robb proposed a $500,000 pilot project to test performance-based pay for two years in school districts that want to try it. The Fairfax County School Board voted to establish a task force and hire consultants to draw up a merit play plan.

Last week the D.C. budget passed by the Senate included $1.5 million for a study of merit pay for teachers. The money was added by Sen. Arlen Specter (R-Pa.), chairman of the Senate D.C. Appropriations subcommittee, but faces an uncertain future in conference with the House.

Simons, who torpedoed the merit pay in the Clark plan a decade ago, said he was not opposed to the new study. He told Specter that he could support a merit pay system "in certain circumstances" but added in an interview later that he merely meant that the idea is one "whose time has come again to be explored."

This apparent flexibility is in line with the recent stance of Albert Shanker, president of the American Federation of Teachers, with which the Washington Teachers Union is affiliated. Although he opposed merit pay for many years, in the past few months Shanker has spoken favorably about Gov. Alexander's master teacher proposal in Tennessee.

Under Alexander's proposal 87 percent of all teachers would be eligible for raises ranging from $1,000 to $7,000 a year. These selections would be made by panels composed of teachers and principals from outside a teachers' own district. Shanker said these provisions remove the objections teachers traditionally have had to merit pay plans, and he added that merit pay may well be the means to gain substantial salary increases.

From 1959 to 1963 Montgomery County had a somewhat similar system, called "career recognition." It offered raises of up to $1,000 a year to teachers with at least 10 years experience who were judged to be outstanding. The judging was done by special panels composed of teachers. Even though about 70 percent of those who sought it received higher pay, teachers complained about the elaborate application process.

The plan was killed on a 4-to-3 vote of the school board. Newly elected conservative members voted against the plan, calling it a discredited innovation, while the three liberals on the board supported it--a reversal of the usual political lineup on the issue now.

Former Washington school superintendent Carl Hansen recalls that the D.C. school system had a merit rating system with small pay supplements for about a decade, ending in the mid-1940s. Hansen said there was "general dissatisfaction" with it both among the teachers who were rated and the supervisors who did the rating.

Last month legislatures in both Florida and California approved merit plans, though California's is limited to a cadre of "mentors" who will take on supervisory duties. The details of Florida's plan must be worked out by a commission.

Amatai Etzioni, a sociologist at George Washington University who has written on education issues, doubts that any of the merit plans for teachers would work satisfactorily.

"Teaching is terribly difficult to evaluate," Etzioni said. "Because in effect there are no objective criteria for doing it. If the principals do it, that's not so good because often the principals are more interested in a cooperative teacher than a good one.

"Do you have peers do it? That has very little significance," Etzioni continued. "There's the whole thing of 'I evaluate you today and you evaluate me tomorrow' . . . . Do you use the students? The fact that students like a teacher may not be a good sign. The students often like somebody who's easy."

As for considering student achievement as a means of rating teachers, Arthur Wise, an education researcher for Rand Corp., said this is bound to be unsatisfactory because of differences in the groups that teachers teach and the limits and uncertainties of the tests themselves.

If standardized tests do become the main ingredient in evaluation, Wise said, that would "create the incentive to do nothing in class except prepare for the tests, and that is not education as I would define it."

When the same issue came up in 1970 Clark replied that student test data should properly be used in measuring teachers, not by itself but along with other evaluations of teacher behavior.

"I don't think it's unfair, and I'm a teacher," Clark said. "The function of a teacher is to teach. And you make your judgment as to the quality of the teacher by the results of that."

Outside public schools, merit pay already is widespread in teaching. The system of ranks--even with pay differences within each rank--is the norm at universities and colleges.

In most private schools teacher pay also depends on individual performance, said Quintin Wilkins, the upper school principal at Sidwell Friends. Pay also varies from field to field, Wilkins said, depending on supply and demand. Sidwell Friends school itself, which employs about 100 teachers, has a pay scale based on years of teaching experience. But for each year on the scale there is a range of about 15 percent, depending on an evaluation of the individual teacher's performance.

The average salary for teachers nationwide now is about $20,500 according to estimates by the NEA. The average in most Washingon area school systems is about $25,000.

"The teachers deserve more than that, so that their salaries would be comparable to other professions," said former Montgomery superintendent Andrews. "But in the real world that just isn't going to happen. We still have to keep our good teachers in the classroom, and the only way to do that is to pay better teachers more.

"We need incentives like every field does," Andrews added. "If somebody has a better idea, I'd like to see it."