Validation of the health literacy scale for diabetes as a criterion-referenced test with standard setting procedures.

OBJECTIVE: To develop and examine the psychometric properties of the Korean Health Literacy Scale for Diabetes Mellitus (KHLS-DM), and to establish reasonable cutoff scores.

METHODS: Initially, 299 items were generated to measure diabetes-related words, numeracy, and information utilization. Content validity assessment and preliminary tests were conducted. After exploratory factor analysis (EFA) and Rasch analysis, the remaining 65 items were administered to a quota sample of 500 diabetic patients aged 40-74 years. The items were narrowed down to 58 items based on an item fit index. To obtain cutoff scores, Jaeger's method and the Bookmark method were employed.

RESULTS: A confirmatory factor analysis (CFA) was performed, and a three-factor model was supported (χ2 /df = 3.891, CFI = 0.92, TLI = 0.91, RMSEA = 0.04). The overall scores ranged from 0 to 58, and two cutoff points were established. The scale exhibited good internal consistency (Cronbach's α = 0.83).

CONCLUSIONS: The KHLS-DM is a reliable and valid measure with cutoff points to classify individuals into three groups (adequate, marginal, and inadequate).

PRACTICE IMPLICATIONS: The standard setting may be useful for researchers to validate health literacy measures in other countries and populations.