Establishing content validity for the nutrition literacy assessment instrument

Introduction Identification of low levels of health literacy is important for effective communication between providers and clients. Assessment instruments for general health literacy are inadequate for use in nutrition education encounters because they do not identify nutrition literacy. The primary objective of this 2-part study was to assess content validity for the Nutrition Literacy Assessment Instrument (NLAI). Methods This study included a 35-item online survey of registered dietitians (134 o f whom answered all questions) and a pilot study in which 5 registered dietitians used the NLAI among 26 clients during nutrition education consultations. To assess agreement with the NLAI by survey participants, we used the following scale: "necessary" (70% agreement), "adequate" (80% agreement), or "good" (90% agreement); comments were analyzed by using content analysis. For the pilot, we made comparisons between subjective assessments, the Rapid Estimate o f Adult Literacy in Medicine (REALM), and the NLAI. Registered dietitians also completed a postpilot-study survey. Results For the online survey, we found good agreement (average, 89.7%) for including each section of the NLAI. All sections accomplished their purpose (average, 81.5%). For the pilot, REALM and NLAI correlation (r = 0.38) was not significant; the subjective assessment of clients by dietitians and NLAI lacked agreement 44% o f the time, and registered dietitians provided instruction on deficient knowledge and skills identified by the NLAI 90% o f the time. Conclusion The NLAI is a content-valid measure of nutrition literacy. Additional validation of the NLAI is important because an objective instrument is needed for identifying nutrition literacy, a construct that appears to be different from health literacy.