SCHOLASTIC Aptitude Test (SAT) scores for college-bound students are down again this year, another indicator that a decade of national education reform has yet to make a difference.Results of the 1991 SAT, released today by the College Board, which sponsors the test, show that average verbal scores reached an all-time low of 422 and average math scores dropped to 474 after four years of no change. Average verbal scores have dropped 21 points since 1969 - nine points since 1985, when national education reforms began in earnest. Average math scores have dropped 19 points since 1969 but have remained relatively stable since 1985, dropping one point. "The fact that [scores] are down in both subjects yet again is a pretty ominous sign of our reform efforts of the past 10 years ... reform is clearly not succeeding," observes Chester E. Finn Jr., who is professor of education and public policy at Vanderbilt University in Nashville, Tenn., and a former assistant secretary of education. While the SAT scores are expected to spark a new round of national handwringing over the state of education, many educators - and the College Board itself - warn that, because not all students take the SAT, the scores are not valid as a single measure of the quality of teaching, educational institutions, or districts. Because of this, some educators are critical of the use of SATs as a measure of the nation's education system. "The SAT is utterly blown out of proportion. It is not even viewed by its maker to be as reliable as a high school transcript," says Grant Wiggins, an educational consultant with the Center on Learning, Assessment, and School Structure. He explains that the SAT is designed as an admission test, not a gauge of curriculum or of past individual achievement. Mr. Finn counters that the SAT scores tend to confirm other indicators of slumping student performance. The 1990 results of the federally sponsored National Assessment of Educational Progress (NAEP) released in June showed that only 14 percent of eighth graders nationally had average proficiency in mathematics. Finn, who is a member of the governing board of NAEP, says the NAEP scores on other subjects due out in September "are not any cheerier." While a poor education system is often blamed for declining scores, a frequently offered explanation is that, with dramatically increasing numbers of students headed to college, a disproportionate share of low achievers take the SAT and drag the averages down. (This year, 42 percent of the nation's graduating seniors took the test.) These lower achievers, it is argued, are minorities and women. Minorities, for example, include those whose first language is not English and those who have fewer opportunities. Women as a group generally have less background in math and science. "It bothers me that people keep using this argument that women and minorities bring the scores down. We argue that it is a content issue; that kids just are not learning," says Emily Feistritzer, director of the National Center for Education Information. She points to white-male test scores as "the real story." The average scores of white males, who traditionally average higher on the tests than any other group, have not improved either, she says. This suggests that declining test averages are not entirely due to declining scores among minorities and women, Ms. Feistritzer says. Since 1985, the white male verbal SAT average has dropped from 454 to 445; the math average dropped from 515 to 512. A wealth of information - interesting if not conclusive - is embedded in the massive amounts of data generated in the scores and the characteristics of this year's 1.1 million test-takers. While overall test averages have gone down, minorities show substantial gains in averages. The test averages of black women, for example, have increased markedly since 1980: 25 points on verbal and 27 on math sections.