New York City received some negative news on Wednesday, when the results of a national science test were released. More than half of the pupils in the fourth-grade tested as “below basic,” a figure that by eighth-grade had ballooned to nearly two-thirds. The results are part of the Trial Urban District Assessment program of the National Assessment of Educational Progress. This test is designed to provide researchers and political leaders with data to guide public policy decisions.

While the scores everywhere are awful and should raise warning flags about how we teach science to American students, we can draw some local conclusions. The grades in science did not occur in a vacuum. They are, I believe, linked to other news we have covered here.

Among the findings in the study is this: White students in New York City are doing much worse than white students in other cities and nationally. Although one rarely hears any discussion about poor performance by white students, this isn’t the first time this has come up in the context of New York City’s public schools.

Results on the state’s fourth-grade English Language Arts test in 2005 went up by nearly 10% in the city, so much that it became a centerpiece of Mayor Bloomberg’s re-election campaign. In essence, it removed education as an election issue, as Mr. Bloomberg’s potential opponents found that their criticisms of the mayor’s education policies rang hollow in the face of such results.

One of the figures highlighted by Chancellor Klein last year was the narrowing gap between white and black fourth-graders by 10 percentage points. This gap, not unique to New York City, is at the center of the national discussion of educational issues. The underlying concept behind the federal No Child Left Behind law is to eliminate these disparities. This is why the performance of schools is determined not just by total “annual yearly progress,” but also on the progress of subgroups such as blacks, Hispanics, low-income children, special education students, and English language learners.

The narrowing of the gap in Gotham wasn’t achieved solely by raising the scores of black students. Half of the gap was closed by a yet-to-be-explained 5 percentage point drop in the performance of white fourth-graders. Obviously, this is not the preferred way to eliminate the disparity. This is related to concerns of parents on Staten Island, where schools have a higher population of white students. The percentage of students scoring at the top level on standardized tests there dropped noticeably this year.

Nobody suggests that the educrats in the Tweed Courthouse are deliberately targeting white students. My theory is that the decline in performance of white students is related to demographic changes — an exodus of higher performing middle- and upper middle class students from the public schools — of all races, but disproportionately of white.

Near the top of the list of things middle-class New Yorkers want in their schools is the presence of programs for academically advanced students, the gifted and talented programs that have been increasingly in the news lately. In response to public pressure, gifted and talented programs that had been slowly starved for a generation are now being revived, but in a way that puts social engineering ahead of the individual performance of students.

There is every indication that the number of minority children in District 3 gifted and talented programs has increased as a result of a new admissions policy. This new policy, which was much in the news last spring, eliminated preference for neighborhood children. The result has been to drive white families out of District 3’s gifted and talented programs and, as my colleague Sarah Garland reported earlier this week, led to the closing of a gifted and talented program in an overwhelmingly minority neighborhood school, P.S. 145.

This happened partly because students from P.S. 145 opted to enroll in the newly available seats that once were earmarked for neighborhood children in schools elsewhere in District 3. The result is fewer total gifted and talented seats in District 3, a much-diminished P.S. 145 in a neighborhood that got a boost from the old gifted program, and a bunch of unhappy parents, mostly white, whose qualified 5-year-old children were excluded from gifted and talented programs in their own neighborhood schools.

Some of these parents, I suspect, are carefully studying the real-estate ads in suburban school districts, or the brochures of private schools here. A lose-lose situation for city schools if ever there was one.