title: Exploring the Measurement Properties of the eHealth Literacy Scale (eHEALS) Among Baby Boomers: A Multinational Test of Measurement Invariance.
abstract: The eHealth Literacy Scale (eHEALS) is one of only a few available measurement scales to assess eHealth literacy. Perhaps due to the relative paucity of such measures and the rising importance of eHealth literacy, the eHEALS is increasingly a choice for inclusion in a range of studies across different groups, cultures, and nations. However, despite its growing popularity, questions have been raised over its theoretical foundations, and the factorial validity and multigroup measurement properties of the scale are yet to be investigated fully.
  
  
  
  The objective of our study was to examine the factorial validity and measurement invariance of the eHEALS among baby boomers (born between 1946 and 1964) in the United States, United Kingdom, and New Zealand who had used the Internet to search for health information in the last 6 months.
  
  
  
  Online questionnaires collected data from a random sample of baby boomers from the 3 countries of interest. The theoretical underpinning to eHEALS comprises social cognitive theory and self-efficacy theory. Close scrutiny of eHEALS with analysis of these theories suggests a 3-factor structure to be worth investigating, which has never before been explored. Structural equation modeling tested a 3-factor structure based on the theoretical underpinning to eHEALS and investigated multinational measurement invariance of the eHEALS.
  
  
  
  We collected responses (N=996) to the questionnaires using random samples from the 3 countries. Results suggest that the eHEALS comprises a 3-factor structure with a measurement model that falls within all relevant fit indices (root mean square error of approximation, RMSEA=.041, comparative fit index, CFI=.986). Additionally, the scale demonstrates metric invariance (RMSEA=.040, CFI=.984, ΔCFI=.002) and even scalar invariance (RMSEA=.042, CFI=.978, ΔCFI=.008).
  
  
  
  To our knowledge, this is the first study to demonstrate multigroup factorial equivalence of the eHEALS, and did so based on data from 3 diverse nations and random samples drawn from an increasingly important cohort. The results give increased confidence to researchers using the scale in a range of eHealth assessment applications from primary care to health promotions.
authors.affiliation: Management School, University of Liverpool, Liverpool, United Kingdom.
authors.forename: Lynn
authors.identifier: 0000-0001-5097-3407
authors.initials: L
authors.lastname: Sudbury-Riley
authors.affiliation: Waikato Management School, University of Waikato, Hamilton, New Zealand.
authors.forename: Mary
authors.identifier: 0000-0001-9591-6334
authors.initials: M
authors.lastname: FitzPatrick
authors.affiliation: Institute of Communication and Health, Faculty of Communication Sciences, University of Lugano, Lugano, Switzerland.
authors.forename: Peter J
authors.identifier: 0000-0003-4281-489X
authors.initials: PJ
authors.lastname: Schulz
mesh_terms: D000367:Age Factors; D000368:Aged; D003197:Computer Literacy / Q000706:statistics & numerical data*; D005260:Female; D063005:Health Information Systems; D057220:Health Literacy / Q000706:statistics & numerical data*; D006293:Health Promotion / Q000379:methods; D006801:Humans; D038622:Internationality; D020407:Internet / Q000706:statistics & numerical data*; D008297:Male; D008875:Middle Aged; D011795:Surveys and Questionnaires; D017216:Telemedicine / Q000706:statistics & numerical data*
keywords: baby boomers; eHEALS; eHealth literacy; health information; health literacy; measurement invariance