Development and validation of a Weight-Specific Health Literacy Instrument (WSHLI)

Objective: Develop/validate a weight-specific health literacy instrument. Methods: The development of weight-specific health literacy measurement consisted of seven phases: (a) a literature review; (b) consultation with weight management experts; (c) generation of an item pool; (d) selection of items via the Delphi method; (e) pilot testing; (f) a national survey; and (g) examination of the psychometric properties of the results. Results: A random sample of 362 Taiwanese adults completed the face-toface survey. The results of factor analysis indicated reasonable good fit of a 2-factor model (χ ² /df = 1.1, p = 0.18; RMSEA = 0.02, CFI = 0.99, TLI = 0.99). Construct validity testing showed that the both factors were significantly correlated with s-MHLS (γ = 0.71, p < 0.001; γ = 0.22, p < 0.001), comprehension (γ = 0.32, p < 0.001: γ = 0.10, p < 0.05), and writing (γ = 0.44, p < 0.001: γ = 0.11, p < 0.05). Predictive validity testing showed that the first factor had significant correlations with weight management efficacy (γ = 0.16, p < 0.001), and three weight management behaviors. The second factor was significantly correlated with weight management efficacy (γ = 0.11, p < 0.05) but not with the 3 weight management behaviors. Conclusions: On the basis of the psychometric results, we conclude that the final version of Weight-Specific Health Literacy Instrument (WSHLI) includes the 13 items. It is a valid and reliable tool for weight management research and evaluation in Mandarin Chinese speaking populations.