The Brief Health Literacy Scale for Adults: Adaptation and Validation of the Health Literacy for School-Aged Children Questionnaire

The Health Literacy for School-Aged Children (HLSAC) is a brief, generic instrument measuring health literacy among school-aged children. Given its brevity and broad conceptualization of health literacy, the HLSAC is a potentially valuable measuring instrument among adults as well. This validation study aimed to adapt the HLSAC questionnaire to an adult population through assessment of content validity and subsequently determine the structural validity of the adapted instrument, the Brief Health Literacy scale for Adults (B-HLA). The content validity of the HLSAC was assessed through interviews with respondents and experts, and the structural validity of the adapted instrument (B-HLA) was evaluated using Rasch analysis. The content validity assessment (n = 25) gave rise to adjustments in the wording of five items. The B-HLA demonstrated an overall misfit to the Rasch model (n = 290). Items 6 and 8 had the poorest individual fits. We found no signs of local dependency or differential item functioning concerning sex, age, education, and native language. The B-HLA demonstrated unidimensionality and ability to discriminate across health literacy levels (PSI = 0.80). Discarding items 6 or 8 resulted in an overall model fit and individual fit of all items. In conclusion, the B-HLA appears to be a valid and reliable instrument for assessing health literacy among adults.