On the Letter-Number Sequencing subtest, a child can simply mimic the examiner and earn credit on the first 10 trials. Is this really working memory?
The early items measure short-term auditory memory, which is a precursor skill to working memory. The 6–7 year old norms demonstrate that children scoring 10 raw score points obtain above average scaled scores; this reflects the developmentally appropriate use of short-term memory prior to the exhibition of working memory. Thus, for younger children, Letter-Number Sequencing may assess short-term memory, a prerequisite skill for the development of working memory. The item set and norms reflect this change as children develop working memory. This is analogous to the difference between Digit Span Forward and Backward, which assesses short-term memory and working memory, respectively. Performance on the early items of Letter-Number Sequencing in younger children may be related to performance on Digit Span Forward with any differences potentially attributable to automaticity of letters as compared to numbers.
