Fairfax County's new school superintendent, Robert R. Spillane, said yesterday that schools in the county must show swift improvements -- including "measurable higher achievement" by students -- or lose forever the public concern that now is focused on the nation's classrooms.

Spillane told county educators they must respond to the pressure created by 11 critical national reports on the status of American education. "This is the decade when we will be remembered as having seized the opportunity because education is on the front burner, or lose the opportunity to raise public education to greatness," he said.

If the schools fail, those reports will amount to "sound and fury signifying nothing," he said in a speech to a management conference of principals and administrators. It was his first major public appearance since he came to Fairfax a month ago from Boston, where he ran the city's public schools.

Spillane, 50, whose nickname is "Bud," was introduced to his staff to the accompaniment of the Budweiser beer commercial jingle, "This Bud's for you." His speech dealt in generalities, reflecting what he has said will be his initial low-key approach to the job.

Fairfax, the 10th largest school system in the country, has "excellence without complacency," he said. But the system lacks the high national profile that the troubled Boston system had, and Spillane's remarks indicated he intends to make the Northern Virginia system more visible.

"Strong leadership and community support have brought Fairfax County public schools not to a lofty pinnacle from which to look down upon other school systems, but into the national arena where public education in this country will be tested and redefined," he said.

"Recognize your extraordinary good fortune to be part of such a school system, but recognize, too, the extraordinary obligation that accompanies your position -- the obligation for national leadership."

The county and other systems must confront an expected national teacher shortage and the lowered status of the teaching profession not just by higher pay, but also by offering better working conditions and in-service training, he said.

Spillane warned that educators must look beyond parents of school-age children for support, because many taxpayers do not have a stake in the schools. Although half of Fairfax households have children in school, the figure nationally is only 25 percent at best, half what it was in the 1950s, he said.

Quoting outlaw Willie Sutton, who said he robbed banks because "that's where the money is," he said the schools must lobby older county residents and business people, because "that's where the support . . . for public education is."

Spillane said the county must continue providing programs for a diverse student body -- the gifted, handicapped, maladjusted and others -- not taking the "safe road of mediocrity" by treating all students alike. He also endorsed merit pay for teachers, saying that not all adults are alike either. Fairfax is experimenting with merit pay, but has not instituted it formally.

Two Fairfax School Board members -- Joy G. Korologos and Katherine Hanley -- praised Spillane's speech and said it reflected the philosophy that persuaded them to hire him this past spring.

"One of his messages was that we can't be parochial about this; we have to look at the larger picture educationally nationally," Korologos said. "So many things are working so well here that we need to spread the good word.