Cognitive Assessment, Psychometrics, Tutorial, Uncategorized, Video

Do Large Subtest Score Differences Invalidate Composite Scores?

A video tutorial that explores the issue of when large differences in subtest scores within a composite tell us to ignore the composite score (Short answer: Not very often).


4 thoughts on “Do Large Subtest Score Differences Invalidate Composite Scores?

  1. Kathy Sarin says:

    Is this approach (for lack of a better word) new? It seems like we were taught not to report FSIQ when there was significant scatter in grad school many years ago, and I still see reports where people say the FSIQ isn’t valid because of scatter. I think the report writer for the WISC-III did an auto text on scatter removing the FSIQ in the report it generated. So this really blew my mind. I shared it with my boss and she said it was a rabbit hole that made her think we shouldn’t report any composite scores at all. Can you clarify when/how this practice changed?

    • This idea has been around for a while. Several empirical demonstrations that scatter does not reduce the validity of the composite score have been published. Zack Roman and I wrote about the idea in detail and provided thorough demonstrations that the idea is correct in “Fine-Tuning Cross-Battery Assessment Procedures: After Follow-Up Testing, Use All Valid Scores, Cohesive or Not”

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