In their 2012 book, “Exam Schools: Inside America’s Most Selective Public High-Schools,”  Chester E. Finn Jr. and Jessica A. Hockett offer a comprehensive look at screened admissions secondary schools across the US by spotlighting a cross-section of educational models.

These range from the statewide residential Illinois Mathematics and Science Academy, to Pine View School for the Gifted in Osprey, FL, which accepts kids in 2nd grade and takes them through 12th, to Thomas Jefferson High-School for Science and Technology in Annandale, VA, regularly cited as America’s top public high school by “US News and World Report.”

They also analyze national trends. More girls go to exam schools than boys. There are proportionally more Black and Asian students attending than are in the overall population. The number of teens eligible for free lunch is slightly less than the average number across the country. The number of students with disabilities, however, is much lower.

But what exam schools and their communities share in common is that there aren’t enough seats to accommodate all who would benefit from an accelerated academic education.

NYC parents, of course, don’t need to wait until high school to see that. Starting in kindergarten, two-thirds of NYC kids who are eligible for Citywide G&T programs are shut out.

Close to 30,000 8th graders take the Specialized High School Admissions Test (SHSAT). Only around 4,000 are offered a seat at one of eight schools.

Yes, there are some excellent Screened schools and Honors programs, which require a combination of state test scores, portfolios and/or interviews to apply, that pick up the slack but, in the end, more are desperately needed.

In 2002, when faced with such demand, Mayor Michael Bloomberg created five new SHSAT schools (or converted existing schools into Exam Schools). His successor, Bill de Blasio, on the other hand, would prefer to see all Exam Schools phased out, in favor of schools that use multiple admissions criteria. He claims this would create more diversity in the student body. He pointedly ignores research that says it would not.

With traditional public schools at a stalemate, could charter schools fill the gap?

Of course not, shout critics! Charter schools cannot be selective! They have to either take all comers or, if demand exceeds supply, hold a lottery.

That is actually not true. There are alternative precedents in the charter school sector. The International Academy in Bloomfield Hills, MI uses a lottery to select which students may sit for their exam, then admits based on scores. The Charter School of Wilmington, DE first assesses all applicants, then holds a lottery. And Benjamin Franklin High School in New Orleans, LA sets an academic bar, then accepts all who reach it.

Currently, NYC students are offered multiple tracks when they apply to public high school. They may take the SHSAT. They can apply separately to LaGuardia School of the Arts. Then there is a general high school application, where students list up to 12 schools in order of preference, including the Screened and Honors programs mentioned above. It’s possible for one student to to get into three public schools: a SHSAT school, LaGuardia, and a third public school.

So why not let charter schools follow traditional public schools’ lead and split into two admission tracks? One that’s open to all, and one that’s exam-based? It has the potential to offer an equally challenging alternative to kids who just missed an SHSAT school by a couple of points.

And since the Mayor is obsessed with his personal definition of  diversity  (the fact that the top SHSAT high school, Stuyvesant, is 70% non-white and over 50% Free Lunch doesn’t match up with his vision of the world, so he ignores that inconvenient truth), I have a modest proposal for him:

Many of the institutions profiled in the book “Exam Schools” lament their lack of diversity, but point out that federal law disallows using race as an admissions factor. However, in NYC, socio-economic status is fair game. One accelerated Citywide K-8, the Brooklyn School of Inquiry, is setting aside 40 percent of their seats to students who qualify for free lunch.

So what if the exam-based charter schools didn’t just take test scores into consideration, but also socio-economic status? What if the highest-scoring kids were ranked in reverse order of their finances, so the neediest get in first?

The charter school exam option would not take kids out of the running for SHSAT and other public schools, or even non-exam charters. It would simply offer them yet another choice, just like the multiple traditional public school tracks do.

Currently, only 1% of U.S. students attend Exam Schools. Even Mensa allows the top 2% to join their allegedly elite intellectual organization! Those numbers would suggest there have got to be many more qualified for accelerated education teens out there than are presently being served. If traditional public schools won’t accommodate them, then the charter sector must.

And what better market than NYC, with its Lake Wobegon numbers of above-average children, to lead the way?