Scale quality: alpha is an inadequate estimate and factor-analytic evidence is needed first of all

Rik Crutzen*, Gjalt-Jorn Ygram Peters

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

109 Citations (Web of Science)

Abstract

Cronbach's alpha is a commonly reported estimate to assess scale quality in health psychology and related disciplines. In this paper, we argue that alpha is an inadequate estimate for both validity and reliability - two key elements of scale quality. Omega is a readily available alternative that can be used for both interval and ordinal data. More importantly, we argue that factor-analytic evidence should be presented before assessing the internal structure of a scale. Finally, pointers for readers and reviewers of manuscripts on making judgements about scale quality are provided and illustrated by examples from the field of health psychology.

Original languageEnglish
Pages (from-to)242-247
Number of pages6
JournalHealth Psychology Review
Volume11
Issue number3
DOIs
Publication statusPublished - 2017

Keywords

  • Scale quality
  • alpha
  • internal consistency
  • validity
  • reliability
  • COEFFICIENT ALPHA
  • RELIABILITY
  • VALIDATION
  • NUMBER
  • ADOLESCENTS
  • CONSTRUCTS
  • VALIDITY
  • ERROR

Cite this