Does anyone know if there are studies about ways ASD may show through in achievement testing, specifically in this case with particular "feel" of writing in the WIAT essay? I would be interested in any sorts of patterns or features of results associated with ASD in both WISC and WIAT tests (or other tests which are not specifically being used to assess ASD) that may be of note to an assessor. And of course particularly in relation to the gifted child.

Caveat: these are my anecdotal clinical observations over years of experience, not necessarily based on a deep, sturdy, objectively sampled and analyzed data set.

That being said, I find that learners on the autistic spectrum often do struggle with the open-ended nature of the essay, especially with certain aspects (not necessarily every aspect in every individual), including idea generation, organization, elaboration, and the personal narrative qualities of the prompt. GT students (and 2e GT/ASD even more so) sometimes get hung up on the absolute factual accuracy of the essay.

I did find this research reference (it's a meta-analysis, so you can poke through the citations, too):
https://www.ncbi.nlm.nih.gov/pubmed/29164435

Thanks AEH, so in this case the child scored 4th percentile for handwritten essay and 99th percentile for a second typed essay. Clearly many things went well with the essay. The suggestion that something about the essay implied ASD is fuzzy, clearly far fuzzier than what can be captured by the standardized scoring system of an academic test. Is perhaps related to drawing the reader in (or not), ie forging social connections... Perhaps that is captured by "personal narrative qualities of the prompt".

This is an observation I have not ever heard before with relation to this sort of testing so I am quite intrigued.