Examination of an eHealth literacy scale and a health literacy scale in a population with moderate to high cardiovascular risk: Rasch analyses.INTRODUCTION
 Item response theory methods, such as the Rasch measurement model, are increasingly used for the psychometric evaluation of scales.  This paper aims to examine the internal construct validity of an eHealth and health literacy scale using Rasch analysis in a population with moderate to high cardiovascular disease risk.


 Overall Rasch model fit as well as five key psychometric properties were analysed: unidimensionality, response thresholds, targeting, differential item functioning and internal consistency.


 The HLQ subscales (except subscale 5) did not fit the Rasch model (χ2: 18.18-60.60, p: 0.00-0.58) and had suboptimal targeting for most subscales.  Rasch analyses demonstrated that the eHEALS has good measures of internal construct validity although it appears to capture different aspects of eHealth literacy (e.g. using eHealth and understanding eHealth). 
Rasch
Item response theory methods, such as the Rasch measurement model, are increasingly used for the psychometric evaluation of scales. 
Rasch measurement model
Item response theory methods, such as the Rasch measurement model, are increasingly used for the psychometric evaluation of scales. 
Item response theory methods