The Other Side of the Bell Curve: Multivariate Base Rates of High Scores on the Delis-Kaplan Executive Function System

Justin E. Karr, Mauricio A. Garcia-Barrera, James A. Holdnack, Grant L. Iverson

Research output: Contribution to journalArticlepeer-review

7 Scopus citations

Abstract

Objective: Previous researchers have examined the frequency at which healthy participants obtain one or more low scores on neuropsychological test batteries, proposing five psychometric principles of multivariate base rates: (a) low scores are common, with their frequency contingent on (b) the low score cutoff used, (c) the number of tests administered/interpreted, and (d) the demographic characteristics and (e) intelligence of participants. The current study explored whether these principles applied to high scores as well, using the Delis-Kaplan Executive Function System (D-KEFS).Method: Multivariate base rates of high scores (≥75th, ≥84th, ≥91st, ≥95th, and ≥98th percentiles) were derived for a three-test, four-test, and full D-KEFS battery, using the adult portion of the normative sample (aged 16-89 years; N = 1050) stratified by education and intelligence. The full D-KEFS battery provides 16 total achievement scores (primary indicators of executive function).Results: High scores occurred commonly for all batteries. For the three-test battery, 24.1% and 12.4% had 1 or more scores ≥95th percentile and ≥98th percentile, respectively. High scores occurred more often for longer batteries: 61.6%, 72.9%, and 87.8% obtained 1 or more scores ≥84th percentile for the three-test, four-test, and full batteries, respectively. The frequency of high scores increased with more education and higher intelligence.Conclusions: The principles of multivariate base rates also applied to high D-KEFS scores: high scores were common and contingent on the cutoff used, number of tests administered/interpreted, and education/intelligence of examinees. Base rates of high scores may help clinicians identify true cognitive strengths and detect cognitive deficits in high functioning people.

Original languageEnglish
Pages (from-to)382-393
Number of pages12
JournalJournal of the International Neuropsychological Society
Volume26
Issue number4
DOIs
StatePublished - Apr 1 2020

Bibliographical note

Publisher Copyright:
Copyright © INS. Published by Cambridge University Press, 2019.

Keywords

  • Assessment
  • Base rates
  • Executive function
  • Neuropsychological tests
  • Norms/normative studies
  • Psychometrics

ASJC Scopus subject areas

  • General Neuroscience
  • Clinical Psychology
  • Clinical Neurology
  • Psychiatry and Mental health

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