Understanding rasch and item response theory models: Applications to the estimation and validation of interval latent trait measures from responses to rating scale questionnaires

Research output: Contribution to journalArticle


Background: Modern psychometric theory is now routinely used in clinical vision research, as well as other areas of health research, to measure latent health states on continuous interval scales from responses to self-report rating scale questionnaires. Two competing theories are commonly employed: Rasch theory and item response theory. Methods: Because the field is currently in transition from using traditional scoring algorithms based on classical test theory to using the more modern approaches, this article offers a tutorial review of Rasch theory and item response theory and of the analytical methods employed by the two theories to estimate and validate measures.

Original languageEnglish (US)
Pages (from-to)1-19
Number of pages19
JournalOphthalmic Epidemiology
Issue number1
Publication statusPublished - Feb 2011



  • Graded response model
  • IRT
  • Partial credit model
  • Patient-reported outcome measure
  • Quality of life
  • Rasch analysis
  • Rating scale model
  • Self-report questionnaire
  • Visual function questionnaire

ASJC Scopus subject areas

  • Ophthalmology
  • Epidemiology

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