Author(s): Steven Hoffman, Flavio F Marsiglia, Matthew C Lambert and Maria Porta
Background and Objective: Psychometrically sound health literacy assessments are widely available in the US for both adults and youth. However, among international youth populations there is a dearth of reliable instruments. This study was undertaken in order to assess the psychometric viability of using the Spanish version of the Newest Vital Sign (NVS; previously validated in the US) among a sample of youth living in Guatemala City. Methods: Analysis is based on 230 youth who were attending various schools within Guatemala City, Guatemala. Rasch modeling was used to estimate item difficulty and discrimination parameters, item fit indices, item-total correlations, and differential item functioning between male and female youth. Results: The majority of the items on the NVS exhibit acceptable properties. The last item demonstrated statistically significant DIF of a practically important magnitude (DIF > |0.43|) suggesting that females are more likely than males to answer the item correctly after controlling for the ‘amount’ of health literacy that the students possess. Conclusion: Those using the NVS among international Spanish-speaking youth populations should be aware that the NVS appears to be appropriate to use in Latin America. Females may tend to have slightly higher scores than males. Additional psychometric testing of the instrument among similar cross-national samples of youth is needed.
