HIDDEN BUT SIGNIFICANT in the local news the other day was word of a tentative contract agreement between the D.C. school board and representatives of the principals and other administrators in the city's public school system. It wasn't that anyone was all that worried about a walkout of the principals--though the worst can always occur. The news, which is good, is that in the agreement there is a clause that would require a "better-than-satisfactory" performance rating for pay raises after the fourth year of employment.

Teachers, take note--because the trend toward better accountability, on terms that can be made acceptable to unions and the school board, should be encouraging not only to parents, students and taxpayers, but also to those teachers and administrators whose competence merits reward.

Under this agreement reached with the D.C. Council of School Officers, which includes principals, assistant principals and central office administrators, a satisfactory rating no longer would be sufficient for a raise to step 5 of an 8-step scale; reviews would be made annually by each administrator's supervisor, and the Council of School Officers would take actions to ensure that ratings are "fair and unbiased."

That last qualification, of course, is critical and remains open to scrutiny and debate. Still, evaluation procedures are not foreign to labor contracts; there is provision on this point in the current teachers' contract, even though the board finds it insufficient. Unions and other professional organizations concerned with the excellence of their members' work do have a stake and should have a cooperative interest in ways of rewarding good performances as well as weeding out those whose poor performances tend to reflect on an entire membership.

Now that contract talks can include money talk as well as proposals for work-rule changes, Washington's teachers, too, should find room to negotiate changes that can improve the lot of the competent educators while discouraging those who do not belong at the head of the class.