Following years of decline, the figures for school-age students covered under the Individuals with Disabilities Education Act (IDEA) has increased as reported by  Christina A. Samuels of EdWeek. The upswing in numbers illustrates that the population has increased since the 2011-2012 school year, particularly in the disability category of autism.

But why? Better diagnosis and reporting, coupled with higher incidents of autism, are likely the main contributors.

The number of disabled students age 6-21 fell to a low in 2011 of 5.67 million, by the 2014-2015 school year the numbers rose to 5.83 million. Interestingly, one third of the national increase came from just one state, New York. The figures are gathered from reports that every state is required to file with the Department of Education. Though statistics seem to indicate a rise in special needs students, it should be noted that the figures can’t always account for an actual increase or decrease, per se. Data is sometimes influenced by policy that may either encourage or discourage special education classification.

However, nationwide between the 2005-2006 and 2014-2015 school years, the figures for students with autism increased 165 percent. During that time frame, there was a 51 percent increase of students with “other health impairments,” that include ADHD, health issues such as epilepsy and mental health issues such as bipolar disorder.

The category that includes learning disabilities, speech and language impairments, behavioral, emotional and intellectual disabilities, generally includes the most students and has been on a downward trend for a decade. The largest group covered under IDEA is students with specific learning disabilities, such as dyslexia, and though this group remains the largest, figures have dropped 6 percent in this category between 2005 and 2015.

Multiple factors could account for the increase in numbers, including shifts in categorization. Some students are being reclassified, as in the case of a child formerly classified as emotionally disturbed, may now be identified as autistic. Moreover, some children who may have never been classified previously, are now meeting new special education guidelines.