my impression of his processing speed was that it was sometimes lightning fast and sometimes dismally slow--and tests of processing speed seemed to be designed to bring out his dismally slow side.
I have one of these! I have said the exact same thing to various professionals in their lives "Slow and deep... also, sometimes lightening fast"
Fast forward to his high school years, where he was able to finish the SAT in half the time and still get all (or almost all) of the questions right.
Mine is horrified at the suggestion that they should have (and use) extra time...
there is an implicit assumption that the person was trying to do their best when taking the test.
Our recent report explicitly states that child worked hard and it was a "Valid" and accurate result... No actual explanation for the very bizarre pattern of strengths and weaknesses. We often hear about a child with some indexes very strong, other's weaker (ie strong VCI, weaker PS or WM). My child managed to have nearly two standard deviations between the two subtests in most indexes (except VCI which was even, and VSI with only one deviation). Even AEH struggled to find a pattern if I recall correctly. Tests that might normally clump together just don't (ie two tests which rely heavily on visual memory and no motor component) and areas that I know are personal strengths have scored relatively poorly compared to relative weakness in day to day life.
I don't think this was a conscious act on the part of my child. But I am not fully on board with the psychologist that the test results accurately reflect best effort or accurately capture my child's strengths and weaknesses. Except in so far as my child has a problem with very variable engagement and performance.