title: Measuring disparities: bias in the Short Form-36v2 among Spanish-speaking medical patients.
abstract: BACKGROUND
  Many national surveys have found substantial differences in self-reported overall health between Spanish-speaking Hispanics and other racial/ethnic groups. However, because cultural and language differences may create measurement bias, it is unclear whether observed differences in self-reported overall health reflect true differences in health.
  
  
  OBJECTIVE
  This study uses a cross-sectional survey to investigate psychometric properties of the Short Form-36v2 for subjects across 4 racial/ethnic and language groups. Multigroup latent variable modeling was used to test increasingly stringent criteria for measurement equivalence.
  
  
  METHODS
  Our sample (N=1281) included 383 non-Hispanic whites, 368 non-Hispanic blacks, 206 Hispanics interviewed in English, and 324 Hispanics interviewed in Spanish recruited from outpatient medical clinics in 2 large urban areas.
  
  
  RESULTS
  We found weak factorial invariance across the 4 groups. However, there was no evidence for strong factorial invariance. The overall fit of the model was substantially worse (change in Comparative Fit Index >0.02, root mean square error of approximation change >0.003) after requiring equal intercepts across all groups. Further comparisons established that the equality constraints on the intercepts for Spanish-speaking Hispanics were responsible for the decrement to model fit.
  
  
  CONCLUSIONS
  Observed differences between SF-36v2 scores for Spanish-speaking Hispanics are systematically biased relative to the other 3 groups. The lack of strong invariance suggests the need for caution when comparing SF-36v2 mean scores of Spanish-speaking Hispanics with those of other groups. However, measurement equivalence testing for this study supports correlational or multivariate latent variable analyses of SF-36v2 responses across all the 4 subgroups, as these analyses require only weak factorial invariance.
authors: Center for Health Care Research and Policy Case Western Reserve University at The Metro Health System, 2500 Metro Health Drive R236A, Cleveland, OH, USA. jsudano@metrohealth.org
authors: Joseph J
authors: JJ
authors: Sudano
authors: Adam
authors: A
authors: Perzynski
authors: Thomas E
authors: TE
authors: Love
authors: Steven A
authors: SA
authors: Lewis
authors: Patrick M
authors: PM
authors: Murray
authors: Gail M
authors: GM
authors: Huber
authors: Bernice
authors: B
authors: Ruo
authors: David W
authors: DW
authors: Baker
mesh_terms: D015982:Bias; D002641:Chicago / Q000453:epidemiology; D003430:Cross-Sectional Studies; D004522:Educational Status; D005163:Factor Analysis, Statistical; D005260:Female; D019538:Health Care Surveys / Q000592:standards* / Q000706:statistics & numerical data; D054625:Healthcare Disparities / Q000592:standards / Q000706:statistics & numerical data*; D006630:Hispanic or Latino / Q000706:statistics & numerical data; D006801:Humans; D007407:Interviews as Topic; D008297:Male; D008875:Middle Aged; D009820:Ohio / Q000453:epidemiology; D011594:Psychometrics; D012959:Socioeconomic Factors; D011795:Surveys and Questionnaires / Q000592:standards