The Department of Defense reported to Congress on Oct 25, 2019 about Comprehensive Autism Care that after 1 year of ABA treatment 76% of those with autism had no change in symptoms and 9% WORSENED by more than 1 standard deviation. This reaffirms Navy Capt. Edward Simmer, chief clinical officer of the Tricare Health Plan, statement in November 2018 that the effectiveness of applied behavioral techniques for autism remains unproven. Year after year, the data says the same thing.
Read the report.
To understand some of the reasoning why ABA does not work, please read the peer reviewed research https://www.tandfonline.com/doi/full/10.1080/23311908.2019.1641258
The failure of the Functional Behavior Assessment also leads to misinformed treatment of Self Injurious Behaviors in autism. https://www.tandfonline.com/doi/full/10.1080/23311908.2019.1682766