Establishing convergent validity of a medication literacy assessment instrument for use within the Nigerian setting

Abstract

Purpose: To establish convergent validity of a previously designed medication literacy instrument for use in Nigeria. Methods: A cross-sectional study was conducted in Zaria, Kaduna State from May to August 2021, with structured instruments administered to conveniently sampled members of the public via one-on-one interviews to collect data. These instruments included a previously designed medication literacy assessment instrument and the Newest Vital Sign United Kingdom version (NVS-UK) health literacy assessment questionnaire. Data obtained was reported using descriptive and inferential statistics. Results: Three hundred respondents were interviewed, majority of whom were females (51 %) and aged between 15-25 (76.6 %). The percentage of correct responses to the NVS-UK questions ranged from 22 to 58.3 %, while the total number of NVS-UK questions answered correctly by respondents ranged from 0 to 6 with a mean of 2.2 ± 1.7. Respondents' NVS-UK scores were associated with their highest level of education completed (p = 0.001). The NVS-UK showed adequate internal consistency (Cronbach's Alpha = 0.7) and validation of the developed medication literacy instrument against the NVS-UK demonstrated a Spearman's rho correlation coefficient of 0.42. Conclusion: The designed instrument is valid and can be used to assess medication literacy within the country.