According to Adam Carey’s story under the headline “Parents fight for autistic siblings to remain in specialist school” (The Age, 4 December 2021), Amisha and Adeerus Ghayur are hoping that their two childen can continue at Latrobe Special Developmental School in Victoria (AU). Why would they not be able to continue? Well, it seems that one child, Zarisha (aged 10) was tested as having an IQ three points higher than the cut score for qualifying for the special school; although an earlier evaluation at age 5 indicated that she performed below the floor of the assessment instrument, now she has an assessed IQ of 73. Her brother, Zeerus, who is now 12, tested at IQ = 66 even though, he (like his sister) had been characterized in 2017 as below the floor of the instrument.

Mr. Carey reported that this siblings have “level 3” autism. Children with such severe involvement usually have co-morbid intellectual disability. There’s lots of research regarding the overlap between ASD and ID (see, for examples, Thurm et al., 2018; Tonnsen et al., 2016; Xie et al., 2020, for papers that cover multiple different aspects of the topic).

This situation raises lots of questions for me. I’ll enumerate some of them here, but please feel free to add other questions (or answers!) in the comments following this post.

1. Why would any education program adhere tightly to cut scores? Shouldn’t decisions about eligibility be based on student need rather than arithmetic score?

2. What’s the measurement error around a score of 73? If it’s a 68% confidence level, the score of 73 should be translated as having 685’ likelhood of falling within a range of 70 to 75 (let’s just say). I think savvy pscyhometricians will say that with particularly low (or high) IQs, there needs to be additional caution in interpeting a score—measurement error is more likely the farther from the mean a score is (and 73 is dang near two standard deviations from the mean), meaning that it occurs very rarely.

3. How was it that these children’s scores improved so much? What happened? As Mr. Carey wrote, “The children’s parents have put intense effort into improving their children’s cognitive ability.” Is it wise that, as payback for that effort, they receive a decision that might undermine that effort?

OK, I could go on and on. Please disscuss in the comments. First, of course, read Mr. Carey’s article.

Sources

Thurm, A., Farmer, C., Salzman, E., Lord, C., & Bishop, S. (2019). State of the field: differentiating intellectual disability from autism spectrum disorder. Frontiers in Psychiatry, 10, 526. https://doi.org/10.3389/fpsyt.2019.00526

Tonnsen, B. L., Boan, A. D., Bradley, C. C., Charles, J., Cohen, A., & Carpenter, L. A. (2016). Prevalence of autism spectrum disorders among children with intellectual disability. American Journal on Intellectual and Developmental Disabilities, 121(6), 487-500. https://doi.org/10.1352/1944-7558-121.6.487

Xie, S., Karlsson, H., Dalman, C., Widman, L., Rai, D., Gardner, R. M., Magnusson, C., Sandin, S., Tabb, L. P., Newschaffer, C. J., & Lee, B. K. (2020). The familial risk of autism spectrum disorder with and without intellectual disability. Autism Research, 13(12), 2242-2250. https://doi.org/10.1002/aur.2417