Measuring health literacy from the communal perspective: initial testing of the Information and Support for Health Actions Questionnaire (ISHAQ)

Measuring health literacy is important in addressing health inequity. However, current measures are developed from the individualistic perspective that values personal autonomy and choice. Applying such measures to people from a communal culture that values collective actions may lead to biased responses. To address this gap, a health literacy measure drawing on the communal perspective was developed in Thailand. With the aim to also develop an equitable measure, a grounded approach including strategies to include people with special needs such as people with chronic illness or physical disabilities, blind people and deaf people, was used. Concept mapping workshops were conducted, involving 254 participants including general community members, people with special needs, health professionals and policymakers. The result was a draft questionnaire of 17 hypothesized scales. Psychometric testing involving a survey of 2,228 participants resulted in a 14-scale questionnaire, the Information and Support for Health Actions Questionnaire (ISHAQ). This paper reports on the psychometric testing of the 14-scale ISHAQ and its supplementary scales for people with special needs. Item difficulty, scale reliability, one-factor confirmatory factor analysis using robust maximum likelihood estimator, and measurement invariance across groups with special needs using the alignment method with Bayesian estimation, were evaluated. A total of 2,262 respondents participated in the survey. Six scales achieved excellent model fit while one with reasonable fit and seven scales achieved reasonable to excellent fit following modifications. Supplementary scales also achieved reasonable to excellent model fit. Reliability for all scales were acceptable to good. Measurement invariance was confirmed for eight scales. With strong validity evidence, the ISHAQ is translated into English and ready for implementation. With the potential to be applied in different settings given cultures exist in a continuum, the ISHAQ can be used for health literacy needs assessment to support intervention development to improve health outcomes and equity.