title: eHealth literacy in chronic disease patients: An item response theory analysis of the eHealth literacy scale (eHEALS).
abstract: Chronic disease patients are affected by low computer and health literacy, which negatively affects their ability to benefit from access to online health information.
  
  
  
  To estimate reliability and confirm model specifications for eHealth Literacy Scale (eHEALS) scores among chronic disease patients using Classical Test (CTT) and Item Response Theory techniques.
  
  
  
  A stratified sample of Black/African American (N=341) and Caucasian (N=343) adults with chronic disease completed an online survey including the eHEALS. Item discrimination was explored using bi-variate correlations and Cronbach's alpha for internal consistency. A categorical confirmatory factor analysis tested a one-factor structure of eHEALS scores. Item characteristic curves, in-fit/outfit statistics, omega coefficient, and item reliability and separation estimates were computed.
  
  
  
  A 1-factor structure of eHEALS was confirmed by statistically significant standardized item loadings, acceptable model fit indices (CFI/TLI>0.90), and 70% variance explained by the model. Item response categories increased with higher theta levels, and there was evidence of acceptable reliability (ω=0.94; item reliability=89; item separation=8.54).
  
  
  
  eHEALS scores are a valid and reliable measure of self-reported eHealth literacy among Internet-using chronic disease patients.
  
  
  
  Providers can use eHEALS to help identify patients' eHealth literacy skills.
authors.affiliation: University of Florida, Department of Health Education and Behavior, PO Box 118210, Gainesville, FL 32611, USA. Electronic address: paigesr190@ufl.edu.
authors.forename: Samantha R
authors.initials: SR
authors.lastname: Paige
authors.affiliation: University of Florida, STEM Translational Communication Center, 2024 Weimer Hall, Gainesville, FL 32611, USA. Electronic address: janicekrieger@jou.ufl.edu.
authors.forename: Janice L
authors.initials: JL
authors.lastname: Krieger
authors.affiliation: University of Florida, Department of Health Education and Behavior, PO Box 118210, Gainesville, FL 32611, USA. Electronic address: mstellefson@ufl.edu.
authors.forename: Michael
authors.initials: M
authors.lastname: Stellefson
authors.affiliation: University of Pennsylvania, Center for Health Behavior Research, 110 Blockley Hall, Philadelphia, PA 19104, USA. Electronic address: alberj@mail.med.upenn.edu.
authors.forename: Julia M
authors.initials: JM
authors.lastname: Alber
mesh_terms: D002908:Chronic Disease; D054626:Consumer Health Information; D005163:Factor Analysis, Statistical; D005260:Female; D057220:Health Literacy / Q000379:methods / Q000706:statistics & numerical data*; D006801:Humans; D020407:Internet; D008297:Male; D011594:Psychometrics / Q000295:instrumentation* / Q000706:statistics & numerical data; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires; D017216:Telemedicine / Q000592:standards*
keywords: Chronic disease; Internal structure; Validity; eHEALS; eHealth literacy