But what she didn't know is that in Texas, unelected state officials have quietly devised a system that has kept thousands of disabled kids like Roanin out of special education.

Walker knew the law was on her side. Since 1975, Congress has required public schools in the United States to provide specialized education services to all eligible children with any type of disability.

She had warned school administrators months earlier that her 5-year-old had been diagnosed with a disability similar to autism. Now they would understand, she thought. Surely they would give him the therapy and counseling he needed.

Heidi Walker was frightened, but as she hurried to the Humble school that day in 2014, she felt strangely relieved.

During the first week of school at Shadow Forest Elementary, a frail kindergartner named Roanin Walker had a meltdown at recess. Overwhelmed by the shrieking and giggling, he hid by the swings and then tried to escape the playground, hitting a classmate and biting a teacher before being restrained.

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.

In the years since its implementation, the rate of Texas kids receiving special education has plummeted from near the national average of 13 percent to the lowest in the country — by far.

Texas is the only state that has ever set a target for special education enrollment, records show.

"We were basically told in a staff meeting that we needed to lower the number of kids in special ed at all costs," said Jamie Womack Williams, who taught in the Tyler Independent School District until 2010. "It was all a numbers game."

More than a dozen teachers and administrators from across the state told the Chronicle they have delayed or denied special education to disabled students in order to stay below the 8.5 percent benchmark. They revealed a variety of methods, from putting kids into a cheaper alternative program known as "Section 504" to persuading parents to pull their children out of public school altogether.

Their efforts, which started in 2004 but have never been publicly announced or explained, have saved the Texas Education Agency billions of dollars but denied vital supports to children with autism, attention deficit hyperactivity disorder, dyslexia, epilepsy, mental illnesses, speech impediments, traumatic brain injuries, even blindness and deafness, a Houston Chronicle investigation has found.

Over a decade ago, the officials arbitrarily decided what percentage of students should get special education services — 8.5 percent — and since then they have forced school districts to comply by strictly auditing those serving too many kids.

"It's completely incompatible with federal law," Kozol said. "It looks as if they're actually punishing districts that meet the needs of kids."

"It's extremely disturbing," said longtime education advocate Jonathan Kozol, who described the policy as a cap on special education meant to save money.

If Texas provided services at the same rate as the rest of the U.S., 250,000 more kids would be getting critical services such as therapy, counseling and one-on-one tutoring.

In 2015, for the first time, it fell to exactly 8.5 percent.

In a statement, Texas Education Agency officials denied they had kept disabled students out of special education and said their guideline calling for enrollments of 8.5 percent was not a cap or a target but an "indicator" of performance by school districts. They said state-by-state comparisons were inappropriate and attributed the state's dramatic declines in special educations enrollments to new teaching techniques that have lowered the number of children with "learning disabilities," such as dyslexia.

In fact, despite the number of children affected, no one has studied Texas' 32 percent drop in special education enrollment.

The Chronicle investigation included a survey of all 50 states, a review of records obtained from the federal government, state governments and three dozen school districts, and interviews with more than 300 experts, educators and parents.

The investigation found that the Texas Education Agency's 8.5 percent enrollment target has led to the systematic denial of services by school districts to tens of thousands of families of every race and class across the state.

Among the findings:

• The benchmark has limited access to special education for children with virtually every type of disability. Texas schools now serve fewer kids with learning disabilities (46 percent lower than in 2004), emotional and mental illnesses (42 percent), orthopedic impairments (39 percent), speech impediments (27 percent), brain injuries (20 percent), hearing defects (15 percent) and visual problems (8 percent).

• Special education rates have fallen to the lowest levels in big cities, where the needs are greatest. Houston ISD and Dallas ISD provide special ed services to just 7.4 percent and 6.9 percent of students, respectively. By comparison, about 19 percent of kids in New York City get services. In all, among the 100 largest school districts in the U.S., only 10 serve fewer than 8.5 percent of their students. All 10 are in Texas.

• Students who don’t speak English at home have been hurt the most. Those children currently make up 17.9 percent of all students in Texas but only 15.4 percent of those in special education. That 15 percent difference is triple the gap that existed when the monitoring system began.

Spokesmen for numerous school districts, including Humble, Houston and Tyler, said they have not denied special ed to any children with disabilities. Several said their rates had declined because they had used early intervention programs to reduce the number of disabled kids.

Education experts told the Chronicle that there is no evidence that the instructional techniques being used in Texas — which are in classrooms nationwide — lower special education percentages.

A Dallas ISD spokeswoman defended that district's low percentage by noting it "falls within the Texas state acceptable range of 0%-8.5%."

After receiving a list of the Chronicle's findings, a U.S. Department of Education spokeswoman said her office would look into the Texas policy.

"It is important that states carry out their responsibilities under the law to ensure that all children who are suspected of having a disability are evaluated in a timely manner to determine eligibility for special education and related services," said the spokeswoman, Dorie Nolt. "Once we have more information from state officials, we will determine if further actions are necessary."

A look at the drop in special education in Texas

Thanks to an arbitrary target imposed more than a decade ago, Texas now gives special education services to a lower percentage of students than any other state.

Hover over the charts below to see who has been affected the most.

Note: The increase in autism identification is less than the nationwide increase, which has been nearly 200 percent.

Moving the number

There is no agreed-upon number for what percentage of kids have a disability that requires special education services.

The best approximation may be 15.4 percent. That's how many U.S. kids ages 2-8 whom doctors have diagnosed with a mental, behavioral or developmental disorder, according to a March 2016 study by the federal Centers for Disease Control and Prevention.

The U.S. has never served that many students in special education, but it has inched closer over time as society has become more aware of disabilities.

By 2000, according to data collected by the federal government, 13.3 percent of kids got some form of specialized education services — even if it was just 20 minutes of speech therapy per week.

In Texas, 12.1 percent of kids got services that year, the ninth-lowest rate in the nation.

Nevertheless, the Texas Education Agency decided the percentage was too high, according to interviews with dozens of former agency employees.

Several said the agency was worried about money. On average, educating a special ed child is twice as expensive, and the federal government pays only one-fifth of the extra costs, leaving the rest to states and school districts — a cost that totaled $3 billion in Texas in 2002.

"There was always a concern about over-identification of special ed students and the costs associated with that," said Ron McMichael, the deputy commissioner for finance at the time.

The concern grew in 2003, when lawmakers cut the TEA's budget by $1.1 billion, forcing it to lay off 15 percent of staffers.

The next year, the agency set the target as one part of a new monitoring protocol known as the Performance-Based Monitoring Analysis System, or PBMAS. The instructions were clear: School districts could get a perfect score on that part of the scorecard by giving special education services to fewer than 8.5 percent of students. If they served more, they would lose points.

Districts that scored poorly on the PBMAS could be fined, visited by regulators, compelled to complete "Corrective Action Plans" or taken over entirely, the system manual said.

The system was developed under Commissioner Shirley Neeley Richardson, an appointee of then-Gov. Rick Perry.

Richardson said in an interview that the special education target was a "first stab" at addressing the problem of over-identification. She said it was data-based and the product of a collaborative process.

But the TEA did not consult the federal government, Texas Legislature or State Board of Education before implementing the policy, records show.

The agency said in its statement that it convened focus groups while creating the PBMAS. But it was unable to produce any documentation of that. None of the educators and advocates interviewed by the Chronicle remembered focus groups.

The TEA also was unable to produce any records about why 8.5 percent was chosen as the target. It acknowledged in its statement that there is no research that establishes 8.5 percent as ideal.

Four agency officials set the benchmark, former employees said: special education director Eugene Lenz; his deputies, Laura Taylor and Kathy Clayton; and accountability chief Criss Cloudt.

The only one who agreed to speak with the Chronicle, Clayton, said the choice of 8.5 percent was not based on research. Instead, she said, it was driven by the statewide average special education enrollment.

Reminded that the statewide average was nearly 12 percent at the time, Clayton paused.

"Well, it was set at a little bit of a reach," she said. "Any time you set a goal, you want to make it a bit of a reach because you're trying to move the number."