Cognitive Assessment, Psychometrics, Tutorial, Video

A Geometric Representation of Composite Scores

Here is a video I made about why composite scores are more extreme than the average of two subtest scores. It is a companion to the paper I wrote with Kevin McGrew about the dangers of averaging subtest scores and thinking of them as composite scores.

The Excel spreadsheet I used in the video can be downloaded here.

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7 thoughts on “A Geometric Representation of Composite Scores

  1. TarTol says:

    Very nice.

    One question: does this representation/calculation work properly in the case of negative correlations?

    Thanks!

  2. Pingback: Why composite scores are more extreme than the average of their parts | Assessing Psyche, Engaging Gauss, Seeking Sophia

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