Developing scales to measure perceived HIV risk and vulnerability among Ethiopian women testing for HIV

HIV prevention services are increasingly being used by individuals in developing countries, but we know very little about how self-assessed HIV risk determines health-seeking behavior. People may feel they are at risk of HIV infection for many reasons, including both risky behavior and anxiety associated with heightened HIV awareness. In order to improve the measurement of perceived HIV risk, we developed scales measuring two constructs. Perceived risk is one's self-assessed likelihood of becoming HIV-infected based on HIV knowledge and behavior. Perceived vulnerability is felt susceptibility to HIV infection even in the absence of risk behavior. Items measuring these constructs were included in a voluntary HIV counseling and testing (VCT) client survey, conducted in mid-2008 with 2027 women attending eight Ethiopian VCT facilities. We also conducted in-depth interviews with 22 women in two of the facilities and added items to the scales based on findings from these interviews. All items were validated in a post-enumeration survey. Factor structures of both constructs were examined using exploratory factor analysis. We also calculated Pearson's correlations between the scales and comparable constructs and behaviors. Cronbach's alpha for the perceived risk scale was 0.87 in the initial survey and 0.89 in the validation survey. For the perceived vulnerability scale, Cronbach's alpha was only 0.66 in the initial survey but increased to 0.74 after adding items indicated by the in-depth interviews. The scales are moderately correlated, indicated by a Pearson's correlation of 0.65. Both scales have high construct validity. Perceived risk has a higher correlation with HIV status than does perceived vulnerability, at 39% vs 28%. Conversely, perceived vulnerability is more highly correlated with HIV salience than is perceived risk, at 39% compared to 25%. These findings suggest perceived HIV risk and perceived HIV vulnerability should be measured separately. More information is needed about how these constructs may motivate people to seek HIV prevention services.