The next big battle over affirmative action may not be in college admissions. On Friday, New York City mayor Bill de Blasio proposed abolishing the system used to admit students to three public high schools in his city that are among the best in the country: Bronx High School of Science, Brooklyn Technical School and Stuyvesant High School. The three schools (and several others in New York City) currently base admissions entirely on scores on a standardized test. That system results in student bodies that are largely Asian-American and that have very few black and Latino students, even though the latter groups make up two-thirds of the city's population.

The debate de Blasio set off may affect not only the high schools (which regularly send graduates to the best colleges in the country) but also larger questions over the role of testing and of diversity in education. De Blasio needs legislative approval for his plans -- and politicians and educators are already lining up on both sides.

In an essay for the education news website Chalkbeat, de Blasio wrote, "Right now, we are living with monumental injustice. The prestigious high schools make 5,000 admissions offers to incoming ninth-graders. Yet, this year just 172 black students and 298 Latino students received offers. This happened in a city where two out of every three eighth-graders in our public schools are Latino or black. There’s also a geographic problem. There are almost 600 middle schools citywide. Yet, half the students admitted to the specialized high schools last year came from just 21 of those schools. For a perfect illustration of disparity: Just 14 percent of students at Bronx Science come from the Bronx. Can anyone defend this? Can anyone look the parent of a Latino or black child in the eye and tell them their precious daughter or son has an equal chance to get into one of their city’s best high schools? Can anyone say this is the America we signed up for?"

The Specialized High School Admissions Test should be scrapped, de Blasio said. He said that it should be replaced with admissions based on middle school grades, state tests and other factors. Such a system, he predicted, would result in notable gains in the number of black and Latino students in the most competitive high schools. (The specialized test has two sections, English/language arts and mathematics. The latter section covers domains of equations and expressions, geometry, number systems, ratio and proportional relationships, and statistics and probability. More information on the test may be found here.)

He also raised questions about the fairness of a test for which wealthy parents (and plenty who are not wealthy but who spend anyway) hire tutors and coaching services. Indeed the same companies known for tutoring on the SAT also offer services on the SHSAT, as the high school test is called. The Princeton Review offers tutoring at $167 an hour. Kaplan offers courses at $999 and packages for in-depth tutoring starting at $2,599. Many other services -- more or less costly -- are also available.

Many parents are proud of sending their children to test prep, and many services cater to Asian families. De Blasio seemed concerned in his essay about offending such parents, writing, "I’d like to stop and say, I admire the many families who scrape and save to pay for test prep. They are trying in every way to support their children. But let’s ask ourselves: Why should families who can ill afford test prep have to spend their money on it? Why should families who can easily afford test prep have an advantage over those that cannot?"

The word "Asian" does not appear in de Blasio's essay announcing that he wants to kill the SHSAT. But a subtext of all the discussion is that Asian-Americans, on average, do so well on the test that they make up large majorities of students at the most competitive high schools, despite making up less than 12 percent of the city's population. Consider the following table on enrollment at Stuyvesant High School. The data are from the New York State Department of Education.

Stuyvesant High School Enrollment by Race/Ethnicity, 2017

Group Percentage Native American 0% Black 1% Latino 3% Asian 75% White 18% Multiracial 3%

Notably, many students at Stuyvesant are low income. Thirty-four percent are eligible for free lunch and another 12 percent are eligible for reduced-price lunches.

While the New York high schools base admission solely on the single test, other elite public high schools -- with broader admissions criteria -- also enroll majority Asian student bodies. Consider Thomas Jefferson High School for Science and Technology, in Northern Virginia, which is regularly called the best high school in the United States and which is also criticized for a lack of diversity.

The school requires applicants to take an admissions test. But those who score at certain levels and have specified middle school grades are then asked to turn in essays, teacher recommendations and information about their activities. The region Thomas Jefferson serves is 19 percent Asian, and more than two-thirds of the students admitted are Asian-American. The share of the local black population is 10 percent, but less than 2 percent of students at Thomas Jefferson are black.

Critics of affirmative action in higher education regularly note the exemplary test scores and grades, on average, of Asian-American students and say that based on those statistics, the share of Asian enrollments should be higher than it is. College admissions officials note that under holistic admissions, no students are admitted based solely on test scores, and that those rejected -- of all races and ethnicities -- include numerous applicants with perfect grades and test scores.

Admissions experts say that simply comparing average test scores is simplistic. The Trump administration is currently investigating Harvard University's admissions system, apparently looking for discrimination against Asian-American applicants.

Many alumni of the specialized high schools in New York City back the use of the test that got them in. They write about the high schools as a meritocracy that encourages academic achievement and that prevents those with connections from winning slots, which are all awarded based on the test scores. "As a result, students learn that the best way to get ahead is through hard work -- even if that means long nights and coffee in the morning. Abolishing the test would cause a substantial change to this culture," says an essay in The Huffington Post.

The essay also argued that focusing on total Asian enrollments ignores the way numerous groups of immigrants (from different countries and with different experiences) are succeeding in the schools. "Specialized high schools promote social mobility and allow immigrants to climb the 'social ladder' and achieve the American dream. When European Jews were immigrating to the United States in the mid-late 1900s, they made up the majority of each class. Today, students from Chinese, Korean, Indian and Pakistani immigrant families fill Stuyvesant classes. Abolishing the SHSAT would displace deserving, hardworking students in order to fill diversity quotas," the essay said.

But de Blasio, in his essay outlining his plan, said that it's time for new definitions of merit -- and to bring more black and Latino students into these high schools.

"Anyone who tells you this is somehow going to lower the standard at these schools is buying into a false and damaging narrative. It’s a narrative that traps students in a grossly unfair environment, asks them to live with the consequences, and actually blames them for it. This perpetuates a dangerous and disgusting myth," wrote the mayor. "So let me be clear. The new system we’re fighting for will raise the bar at the specialized high schools in every way. The pool of talent is going to expand widely and rapidly. That’s going to up the level of competition. The students who emerge from the new process will make these schools even stronger."