Trends in autism prevalence: diagnostic substitution revisited.

The team looked at British Columbia school records from 1996 to 2006.

They counted how many kids carried the special-ed code for autism each year.

They also tracked codes for intellectual disability, speech delay, and other needs.

Autism prevalence in schools jumped from 12 to 43 kids per 10,000.

At least one-third of that jump came from re-labeling.

Children once coded as intellectually disabled or language delayed now carried the autism code.

Williams et al. (2002) saw the same swap in California a decade earlier.

Their autism numbers rose while intellectual-disability numbers fell in lock-step.

Wong et al. (2009) later checked California state files and found no such shift, but they looked at different records.

School data show re-labeling; state disability files do not.

Ouellette-Kuntz et al. (2014) then showed the Canadian climb kept going after 2006, so the trend did not stop.

When you read rising autism rates, remember one-third may be kids we already served under a different name.

Use this fact when you talk to administrators.

Funding and staffing requests should count the whole special-ed population, not just the autism line.