The Autism Diagnostic Interview-Revised and the Childhood Autism Rating Scale: differences between diagnostic systems and comparison between genders.

The team compared two gold-standard autism tools: the ADI-R parent interview and the CARS observation scale. They gave both to the same group of children who were being checked for autism.

Then they looked at how often the two tests agreed and whether boys and girls scored differently.

The tools matched on about 86 percent of cases. When they did not match, it was usually because one test was just above the cut-off and the other just below.

Boys and girls with the same age got nearly identical scores on both tools. No gender gap showed up once age was held steady.

Siegel et al. (1986) had already shown that CARS clearly separates kids with autism from kids with intellectual disability alone. Pilowsky et al. (1998) now adds that CARS and ADI-R usually tell the same story, so you can trust either one.

Hus et al. (2013) later found that younger kids and kids with less language get higher ADI-R scores. That means the small disagreements T et al. saw could partly come from child traits, not tool flaws.

Agiovlasitis et al. (2025) looked at the newer ADOS-II and found boys score higher than girls. This seems to clash with T et al., who found no gender gap. The difference is the tool: ADOS-II uses live play, while ADI-R and CARS rely on history and observation. Girls may mask better during play, so the gap only shows up on ADOS-II.

You do not need to give families both ADI-R and CARS in the same assessment battery. Pick one, use it well, and move on. If you choose ADI-R, remember that younger or less-verbal kids can score higher, so interpret with care. Finally, when you use ADOS-II, keep the possible girl-masking effect in mind and gather extra history before you rule autism out.