I would not worry about processing speed at all. It is generally lower than the other 3 scales. (wisc-iv essentials- assessment)
I also most likely wouldn't *worry* about it in this instance - but fwiw, the degree to which your ds' PSI is lower than the other scores may very well be indicating something significant. (FWIW I have a ds with dysgraphia/DCD and a dd with vision issues; both have significant gaps in PSI vs PRI/VIQ). Without knowing the subtest scores, it's all just a guess but fwiw, I suspect your ds' Irlen Syndrome may have impacted his processing speed scores. Symbol Search is a subtest that requires a student to find matching symbols in a field of random symbols - similar to "Where's Waldo" - my dd who has the vision challenges tanked that particular subtest. The Coding subtest requires a student to copy simple symbols, and is timed - so a child who has difficult copying for any reason (including vision) may have a depressed score on coding. It's not anything to "worry" about since there is most likely a logical explanation for why the subtest score is low relative to other subtest scores, but it's good to understand why the score is low in the context of your child's strengths and challenges, and also good data to have when you advocate for your child - it's essentially "proof" of the impact of a challenge.
That is reassuring processing speed is normally lower.
FWIW, we hear a lot on these forums about lower processing speed being lower as a normal thing, but fwiw, after reading the forums here for a long time, most of the instances of relatively lower processing speed scores I've seen are from parents of 2e students who have some type of challenge that impacts the processing speed. I'd also consider the degree of relative low too - most of what I've read is that any difference between subtests/etc on the WISC that is less than 1 SD is nothing to think twice about, but greater than 1 - 1.5 SD is potentially an indication of some type of challenge. I wouldn't dismiss a relative dip of this magnitude as "normal" until I'd really thought through the full results of the testing, read the tester's full report, thought through what each type of test actually asks the student to do, and related that back to what I knew of my child's particular set of challenges.
polarbear
