A scale to assist the diagnosis of autism and Asperger's disorder in adults (RAADS): a pilot study.

Ritvo et al. (2008) built a 78-question self-rating scale for adults. They call it RAADS. It asks about social habits, sensory issues, and narrow interests.

The team tested RAADS on adults who already had an autism or Asperger diagnosis. They wanted to see if the scale could spot these conditions and tell them apart.

RAADS caught most adults with autism or Asperger's. It also correctly ruled out most adults who did not have either condition.

The scale could not separate autism from Asperger's. Scores for both groups landed in the same range, so you still need other tools for that job.

Hirota et al. (2018) later looked at every adult autism screener. Only three tools had solid backup studies. RAADS was one of them, so the field still trusts it.

Riches et al. (2016) took the same idea to adults with intellectual disability. They paired DiBAS-R and ACL to boost accuracy, just like RAADS tries to do with its one long form.

Saemundsen et al. (2003) showed that even gold-standard tools like ADI-R and CARS only agree about two-thirds of the time. That context helps explain why RAADS cannot split autism from Asperger's—most tools struggle with fine lines.

If you assess adults who wonder if they are on the spectrum, RAADS gives a quick first signal. Use it as a screen, not a verdict. Pair it with an interview or observation tool when you need to tell autism from Asperger's or rule out social anxiety. The scale saves clinic time and helps clients feel heard.