Person Ability Scores as an Alternative to Norm-Referenced Scores as Outcome Measures in Studies of Neurodevelopmental Disorders.

Journal Article (Journal Article)

Although norm-referenced scores are essential to the identification of disability, they possess several features which affect their sensitivity to change. Norm-referenced scores often decrease over time among people with neurodevelopmental disorders who exhibit slower-than-average increases in ability. Further, the reliability of norm-referenced scores is lower at the tails of the distribution, resulting in floor effects and increased measurement error for people with neurodevelopmental disorders. In contrast, the person ability scores generated during the process of constructing a standardized test with item response theory are designed to assess change. We illustrate these limitations of norm-referenced scores, and relative advantages of ability scores, using data from studies of autism spectrum disorder and creatine transporter deficiency.

Full Text

Duke Authors

Cited Authors

  • Farmer, CA; Kaat, AJ; Thurm, A; Anselm, I; Akshoomoff, N; Bennett, A; Berry, L; Bruchey, A; Barshop, BA; Berry-Kravis, E; Bianconi, S; Cecil, KM; Davis, RJ; Ficicioglu, C; Porter, FD; Wainer, A; Goin-Kochel, RP; Leonczyk, C; Guthrie, W; Koeberl, D; Love-Nichols, J; Mamak, E; Mercimek-Andrews, S; Thomas, RP; Spiridigliozzi, GA; Sullivan, N; Sutton, VR; Udhnani, MD; Waisbren, SE; Miller, JS

Published Date

  • November 1, 2020

Published In

Volume / Issue

  • 125 / 6

Start / End Page

  • 475 - 480

PubMed ID

  • 33211814

Electronic International Standard Serial Number (EISSN)

  • 1944-7558

Digital Object Identifier (DOI)

  • 10.1352/1944-7558-125.6.475


  • eng

Conference Location

  • United States