Health Literacy Instrument for Adults-Short Form (HELIA-SF): Development and psychometric properties

Since usually health literacy should be assessed in complex health care settings, this study aimed to develop a short version of the Health Literacy Instrument for Adults (HELIA-SF).

In this methodological study, the research team selected a number of items from the main instrument covering the main constructs of the HELIA. The selection was based on the most relevant items to each construct. A group of 12 experts and ten adults assessed content and face validity respectively. Exploratory and confirmatory factor analysis was performed to assess structural validity. The reliability of the instruments was evaluated by internal correlation (Cronbach's alpha coefficient) and intraclass correlation (ICC).

A nine-item questionnaire was developed. Experts identified the content validity of the short version as desirable (the CVR was more than 0.56 the CVI was more than 0.79). Also, the face validity as assessed by ten adults was satisfactory. The results obtained from exploratory factor analysis showed a two-factor structure for the questionnaire namely basic skills and decision-making skills that jointly accounted for about 61% of variance observed. Furthermore, the confirmatory factor analysis indicated acceptable fit indexes for the data: X2/df =20/2, GFI=95/0, CFI=97/0, NFI=95/0, NNFI=96/0, SRMR=068/0, and RMSEA=074/0. The Cronbach's alpha coefficient and ICC for each of the two dimensions were satisfactory (alpha = 0.84 and 0.81 and ICC = 0.85 and 0.82). The values for the whole items were 0.91 and 0.81, respectively.

The HELIA-SF, including nine items and two subscales (basic skills and decision-making skills) was found to be reliable and valid instrument to measure health literacy in adults. This version is suitable for measuring health literacy in different urban and rural population groups due to its short and concise nature.