The gap between self-reported and objective measures of disease status in India

Researchers interested in the effect of health on various life outcomes (such as employment, earnings and life satisfaction) often use self-reported health and disease status as an indicator of true, underlying health status. Self-reports appear to be reasonable measures of overall health. For example, self-assessed overall health has been found to be a reliable predictor of mortality. However, the validity of self-reports is questionable when investigating specific diseases such as diabetes and hypertension. A small and nascent body of research comparing self-reported status on certain diseases with the true status based on clinical diagnoses has found significant gaps. These validation exercises predominantly use data from high-income countries. In this paper, we use survey data from India to compare self-reports of disease prevalence to diagnostic tests conducted on the same individuals. We focus on hypertension and lung disease, two of the primary causes of death in India. We find that self-reported measures substantially understate the true disease burden for both conditions. The attenuation bias from using self-reports is over 80 percent for both diseases, and bigger than estimates from high-income countries. We test and reject the hypothesis that self-reports of the disease status are identical to the true disease status in expectation. We identify characteristics associated with false negative reporting (reporting not having the disease but testing positive for it) for both diseases. The large awareness gap between self-reports and true disease burden indicates multiple deficiencies in India's public health policy. The survey data depicts limited access to medical facilities, high levels of health illiteracy, low rates of health insurance, and other barriers related to poverty and lack of equity in the delivery of health services. These factors prevent timely intervention for managing health and controlling disease, invariably leading to morbidity and often to premature death.