Houston schools provide special education services to a lower percentage of students than schools in virtually any other big city in America. Only Dallas serves fewer than Houston's 7.26 percent. The national average is 13 percent.

And at Attucks Middle School in south Houston, longtime language arts teacher Thomas Iocca says he was ordered to remove children from special education at random.

At Garden Oaks Montessori School in north Houston, retired assistant principal Kathy Drago says she was informed that only two kids could be evaluated per month.

At Poe Elementary School in west Houston, former social worker Marsha Baumann says she was told repeatedly that students could not be evaluated for special education.

To accomplish the objective, HISD officials slashed hundreds of positions from the special education department, dissuaded evaluators from diagnosing disabilities until second grade and created a list of "exclusionary factors" that disqualify students from getting services, among other tactics described in district documents, court records and dozens of interviews.

Records show the largest school district in Texas enthusiastically embraced a controversial state policy that has driven special education enrollments to the lowest in the United States. In fact, after HISD officials reduced their enrollment rate from 10 percent to the Texas Education Agency's 8.5 percent target, they set an even more restrictive standard: 8 percent.

But a Houston Chronicle investigation has found that HISD achieved its low special education rate by deliberately discouraging and delaying evaluations in pursuit of goals that have clearly denied critical services to thousands of children with disabilities.

For months, as special education has come under increasing scrutiny in Texas, Houston Independent School District officials have described their percentage as a good thing, saying it is the product of robust early interventions that have helped students without labeling them.

In Texas, unelected state officials have devised a system that has kept thousands of disabled kids out of special education. Read other installments in the series here.

HISD also pressured teachers to reduce "over-identification" of African-Americans in special education, despite research suggesting that black students may be more prone to disabilities. The district never made it a goal to fix the significant under-representation of Hispanics in special ed, records and interviews show.

In all, 41 current and former HISD employees told the Chronicle that the district has kept special education rates arbitrarily low. Almost all of them said they saw kids shut out of needed services.

The former superintendents who presided over the special education drop, Abelardo Saavedra and Terry Grier, denied trying to lower the numbers. Both deflected specific questions, saying they could not remember details.

Grier said he didn't even remember the massive special education budget cuts that he ordered in 2011.

At the time, he called the cuts "right-sizing" necessitated by years of drops in special education students. But a data analysis shows the cuts significantly increased the special ed student-to-teacher ratio — and hastened a further decline in students.

The year after the cuts, HISD officials evaluated almost 50 percent fewer students for special ed: They evaluated 2,943 in the 2010-11 year. They tested just 1,572 in 2011-12.

Current district officials, including newly hired Superintendent Richard Carranza, declined to comment.

In September, before the Chronicle first reported that the state had quietly set the 8.5 percent benchmark in 2004, HISD special education director Sowmya Kumar defended the target, saying in an interview that it helped indicate whether special ed was "an area that you need to do something about."

After a public outcry over the benchmark, district officials said they opposed it, although they continued to defend their own practices.

Kumar, who was hired by Grier in 2010, has repeatedly said the district's special education reduction is part of a nationwide trend, a claim contradicted by federal data.

She also said in September that special ed is actually harmful because teachers have lower expectations for kids with labels.

"If the disability label was going to produce better results for kids, then we should have all kids line up. Unfortunately, that's not the case," Kumar said, noting that special ed students score worse on standardized tests than kids without disabilities. "Special education does not deliver better outcomes for kids."

National education experts took exception to her statement about labeling and expressed concern over HISD's low special education enrollment.

"Wow," former Boston Public Schools Superintendent Carol Johnson said. "Seven percent is almost unfathomable."

Several Houston school board members said they were outraged by the Chronicle's findings. Anna Eastman, Michael Lunceford and Rhonda Skillern-Jones, as well as member-elect Anne Sung, all vowed to take action.

"We need to address this," Eastman said.

Former social worker Marsha Baumann talks about student being left out of special ed

Rebecca Amstutz will never forget the first time she heard about the Texas Education Agency's 8.5 percent special education enrollment benchmark.

It was 2006, and Amstutz was teaching math at Hogg Middle School in the Heights. She had a sixth-grader who seemed bright but was struggling in her class, making her suspect a disability might be holding the student back. She approached a colleague to ask about the special education referral process. She was stunned by the response.

"'Don't bother,'" she remembers being told. "'They won't even take the request. Remember the cap.'"

Federal law requires schools to evaluate all students suspected of having a disability. The law even requires districts to search out and screen potentially disabled children, including those in private school or not in school at all.

But Amstutz, who retired in 2013 after 27 years with HISD, said that in her final years in the district, her attempts to get students evaluated were routinely rejected because more than 8.5 percent of the school's students were already in special ed.

Her experience speaks to how seriously HISD takes the benchmark.

When the state set the target in 2004, about 21,000 of HISD's 210,000 students were in special education, statistics show. It took HISD just four years to move from that 10 percent rate to below 8.5 percent, a difference of more than 3,000 kids.

Then HISD officials set a new goal.

In 2010, Grier hired a Harvard University professor to audit HISD's special education department and then asked Kumar to write a strategic plan.

The audit noted HISD's small special ed rate, but then defended it — by citing the TEA benchmark. "(HISD's) percentage is also consistent with Texas Education Agency guidelines," the audit said.

Kumar's Comprehensive Program Improvement Plan, which she completed during the 2011-12 school year, included a goal similar to the TEA target but more restrictive.

"Maintain the percent of students with disabilities at 8% of the district's enrollment," the plan said, according to a copy obtained by the Chronicle.

The goal was disseminated throughout the district and articulated to a Special Education Community Advisory Committee, two members said.

"They always had that magic number that they wanted to keep in (special ed)," committee member Sari Obermeyer said.

Most rank-and-file HISD educators interviewed by the Chronicle said they were not told specifically about a target percentage. But more than a dozen said they were.

At Attucks Middle School, everybody knew about the "cap," said Iocca, the longtime language arts teacher. Teachers sarcastically referred to it as "TEA's attempt to legislate the disappearance of special ed students," he said.

"We had long, agonizing meetings where we tried to push as many special ed students as we could into general education just to meet TEA's mandate," said Iocca, who taught in HISD for 29 years before retiring. "You realize, this is not the best environment for these kids, but there's nothing you can do about it."

Teachers tried to fight back, but they soon realized that resistance would bring trouble, Iocca said.

"The principals and the other administrators had a pretty good idea of what was going on," he said. "If teachers referred too many kids, they'd say, 'Maybe it's a classroom-management issue.' ... Your efficiency as a teacher was questioned."

HISD principals also have been punished for special ed "over-identification," said Kristi Rangel, a former principal of Kashmere Gardens Elementary, a northeast Houston school where 99 percent of students are minorities.

Rangel recalled constant pressure to reduce special education rates. Once, when a fellow principal was fired, she was told by colleagues that it was because he refused to comply with the target.

"School districts have to do what the TEA tells them to do," said Rangel, who left in 2015 to join the Houston Health Department. "It's the reality."

Only 5.7 percent of Kashmere Gardens Elementary students now receive special education.

Listen: Houston ISD Special Education Director discusses the reduction of services

Houston ISD's effort to curtail special education began soon after the state set its 8.5 percent target. Within months, Saavedra and his special ed director, Carolyn Guess, increased the paperwork required to get students evaluated and created committees to vet evaluation requests and decide whether to approve them, among other moves.

"The process for getting an evaluation became very difficult and time-consuming," said Claudia Anderson, who worked in a variety of roles over a 34-year HISD career and retired in June. "It was all about delay, delay, delay."

Then, after enrollments started to fall, HISD rolled out a new evaluation request form. The form, which is still in use, prohibits teachers from filing a request until they certify that a student's struggles in school could not possibly be explained by trauma, moving between different schools, "any variables related to the student's medical history," "any variables related to family history," "the student's cultural background" or other "exclusionary factors."

Special education evaluations are supposed to check for the presence of those issues. But several experts said HISD's form is so broad that it likely deters teachers from requesting evaluations. Some suggested it might be illegal.

"Such a criterion includes just about each and every student not only in HISD but in just about any school," said John Lloyd of the University of Virginia.

More recently, under Grier and Kumar, several diagnosticians said they were urged not to diagnose students with learning disabilities until second grade. Problems before then could be caused by a lot of things, the diagnosticians said they were told.

Employees also have testified about that in court cases involving special ed denials. Evaluation specialist Katherine Bell said in a 2013 case that she was "not supposed to identify dyslexia" before second grade, records show.

Federal law does not include any grade line and encourages schools to identify disabilities as early as possible.

Experts, including professor Barbara Pazey of the University of Texas, quoted research saying dyslexia can be diagnosed prior to second grade.

But the most harmful delay tactic, according to employees, has been Response to Intervention, a new set of regular-education teaching techniques in use across the country that have been championed in Houston by Kumar.

Federal officials have approved RTI, with one caveat: Schools cannot require teachers to try RTI before requesting a kid be evaluated for special ed.

That is exactly what has happened in HISD, according to numerous current and former staffers.

"RTI was a huge roadblock," said Renee Tappe, who retired in 2015 after 35 years in special education at HISD. "Every now and again, it would help a kid a little bit, but when you look at the number of kids denied, it's not even close to being worth it."

When delay is no longer possible, several HISD staffers said they have been encouraged to suspend or expel students who act out instead of evaluating them for special ed. A 2015 TEA probe confirmed HISD has done that multiple times, including by charging kids with truancy, according to records obtained by the Chronicle.

The district also has started increasingly serving students with dyslexia in Section 504, a less robust and less accountable program than special ed.

Veteran employees also pointed to the budget cuts as a way that HISD has intentionally lowered special education rates. Officials have cut nearly 600 special ed positions over the past decade, a 40 percent drop that has been even sharper than the dip in students, statistics show.

Cuts in the number of diagnosticians have made it harder to get evaluations, while cuts in other areas have diminished the amount and qualify of services available to disabled students, the staffers said.

Today, HISD — the seventh-largest school district in the country — does not employ a single Board Certified Behavior Analyst, a specialist certified to provide the therapy that is seen as the best way to serve autistic students.

The district also has set an arbitrary threshold that forbids special education students from receiving the most intensive types of supports unless their IQ is below 60 in two different areas, records show.

"The teachers pretty much knew that (special ed students) wouldn't get any services. So they thought, 'Why would I go through all this to get the kid identified?' All the paperwork and the rigmarole," said diagnostician Mary Ann Ryerson, who retired in 2015.

Ryerson and others said they were particularly upset with the IQ threshold, in part because the commonly accepted national standard for when a student needs help is an IQ of 70. Setting the threshold at 60 was "shocking" and "illegal," Ryerson said.

Together, the moves have helped drop HISD’s special education population by about 5,000 students, even as the district’s total enrollment has grown.

Today, most major cities give special education services to students at a rate twice as high as in Houston.

If the district provided special ed at the same rate as the national average, more than 12,000 more Houston children would be getting services.