Family income appears to be a major factor influencing whether parents will seek mediation or due process in special education disputes with their child’s school district.

A nationwide survey of over 500 parents with children on the autism spectrum finds that families earning more than $100,000 a year are significantly more likely to pursue litigation compared to those with incomes that are half that level.

The findings published recently in the Journal of Autism and Developmental Disorders may point to fundamental inequities in the special education process, researchers said.

“That’s a huge problem, to see that parents who come from low-income backgrounds have less access to these safeguards,” said Meghan Burke of the University of Illinois who conducted the research. “Due process and mediation are definitely last resorts for parents and schools to resolve their differences, but you want it to be an equitable resort. The playing field needs to be leveled so that lower-income families have access to pro bono and sliding-scale attorneys who can help them file, if that’s something that they need to do.”

Under the Individuals with Disabilities Education Act, parents can pursue mediation or due process if they believe that their child is not being provided an appropriate educational program by their school district. However, both approaches can be complicated and costly, with an average due process hearing costing parents and schools an estimated $60,000, according to the study.

More than a quarter of parents surveyed for the study said they had participated in mediation or due process.

Beyond income, the survey found that parents were nearly twice as likely to pursue litigation if they had a child who spent less than 20 percent of their time in mainstream classrooms.

Families were also significantly more likely to resort to mediation or due process if they had an older child and in cases where kids were more withdrawn or anxious as opposed to those who displayed physical behaviors or verbal aggression, the study found.