Kimberly Bertha, a special education teacher at Denver Omar D. Blair Charter School, works with a students in 2010. (Denver Post file)

The loudest and most valid criticism against charter schools has been that they don’t serve all kids, especially children with special needs.

Nationally, students with disabilities make up about 11 percent of the population in district-run schools but only 8 percent of charter enrollment.

In Colorado, that gap still exists, though changes are underway.

In Denver, Superintendent Tom Boasberg, a charter proponent, has insisted that all schools in the district be available to all students, including charters, which are public schools with different governing structures.

The district has struggled with this over the years. In 2009, only two students with significant disabilities were among Denver’s 7,000 charter students.

That has thankfully changed as a handful of charters have added programs specifically for students with more severe disabilities.

But a recent study by the Seattle-based Center on Reinventing Public Education found a two-point gap exists between the number of kindergartners with special needs in charter schools compared with those in district-run schools. That gap doubles by middle school. The study suggests several possible reasons for the gap, including that students with special needs are less likely to apply to charter schools and that charters are less likely to classify students as being in special ed.

The study doesn’t conclude that disabled students are being counseled out, which has been suspected by charter critics.

Yet, the goal for many parents is not just to have their child with special needs in the same building as typical kids. It is also to have them in the same class, learning the same material.

The prevailing model in Colorado now is to enroll children with severe disabilities in “center-based” schools, which offer more services, special educators and groups of professionals. Generally, those children are pulled from assigned classrooms for therapies or more directed instruction.

But the pull-out model is discriminatory and perpetuates a divided society. I’ve never understood why the money spent on keeping a separate classroom couldn’t be better spent on resources in the classroom for more special-education teachers.

It is wonderful news, then, that Denver is looking to change this. An all-inclusive charter school was recently approved by Denver’s school board.

REACH Charter School (Reimagining Excellence for All in a Community with Heart) will keep kids in the classroom with their non-disabled peers, pushing therapies and targeted instruction into the classroom rather than pulling the kids out. The school is being developed by the folks who run Sewall Child Development Center, one of a handful of inclusive preschools in the metro area.

REACH already has a building in Congress Park, a principal with experience in inclusion, and is searching for funding. It opens in the fall of 2015 with preschoolers to first-graders and will add a grade every year thereafter, through fifth grade.

The student population will be 30 percent special ed, 57 percent free and reduced lunch, and 27 percent English learners.

Though disability advocates are celebrating, DPS officials worry REACH could have trouble attracting kids without disabilities. It shouldn’t be a problem. A school with expanded supports in the classroom will help all kids, said Heidi Heissenbuttel, Sewall’s CEO. And that will be an added bonus for everyone.

Inclusion has been proven to work in classrooms around the world. And it is time charter schools, originally intended to foster innovation, figured that out.