title: Measurement invariance of the Illness Invalidation Inventory (3*I) across language, rheumatic disease and gender.
abstract: OBJECTIVE
  The Illness Invalidation Inventory (3*I) assesses patients' perception of responses of others that are perceived as denying, lecturing, not supporting and not acknowledging the condition of the patient. It includes two factors: 'discounting' and 'lack of understanding'. In order to use the 3*I to compare and pool scores across groups and countries, the questionnaire must have measurement invariance; that is, it should measure identical concepts with the same factor structure across groups. The aim of this study was to examine measurement invariance of the 3*I across rheumatic diseases, gender and languages.
  
  
  METHODS
  Participants with rheumatic disease from various countries completed an online study using the 3*I, which was presented in Dutch, English, French, German, Portuguese and Spanish; 6057 people with rheumatic diseases participated. Single and multiple group confirmatory factor analyses were used to test the factorial structure and measurement invariance of the 3*I with Mplus.
  
  
  RESULTS
  The model with strong measurement invariance, that is, equal factor loadings and thresholds (distribution cut-points) across gender and rheumatic disease (fibromyalgia vs other rheumatic diseases) had the best fit estimates for the Dutch version, and good fit estimates across the six language versions.
  
  
  CONCLUSIONS
  The 3*I showed measurement invariance across gender, rheumatic disease and language. Therefore, it is appropriate to compare and pool scores of the 3*I across groups. Future research may use the questionnaire to examine antecedents and consequences of invalidation as well as the effect of treatments targeting invalidation.
authors: Department of Clinical and Health Psychology, Utrecht University, , Utrecht, The Netherlands.
authors: Marianne Belia
authors: MB
authors: Kool
authors: Rens
authors: R
authors: van de Schoot
authors: Isabel
authors: I
authors: López-Chicheri García
authors: Ricarda
authors: R
authors: Mewes
authors: José A P
authors: JA
authors: Da Silva
authors: Karoline
authors: K
authors: Vangronsveld
authors: Andreas A J
authors: AA
authors: Wismeijer
authors: Mark A
authors: MA
authors: Lumley
authors: Henriët
authors: H
authors: van Middendorp
authors: Johannes W J
authors: JW
authors: Bijlsma
authors: Geert
authors: G
authors: Crombez
authors: Winfried
authors: W
authors: Rief
authors: Rinie
authors: R
authors: Geenen
mesh_terms: D000328:Adult; D001294:Attitude to Health; D032882:Comprehension; D004645:Empathy; D005260:Female; D005356:Fibromyalgia / Q000523:psychology; D006801:Humans; D007802:Language; D008297:Male; D008875:Middle Aged; D009426:Netherlands; D011594:Psychometrics; D015203:Reproducibility of Results; D012216:Rheumatic Diseases / Q000523:psychology*; D057566:Self Report; D012737:Sex Factors; D012944:Social Support; D011795:Surveys and Questionnaires
keywords: Fibromyalgis/Pain Syndromes; Osteoarthritis; Psychology; Rheumatoid Arthritis