An empirical investigation of health dynamics of elders in China

Using data from the China Health and Nutrition Survey (CHNS), an index of health frailty is developed for individuals ages fifty-five and older. The evolution of the Frailty Index with age is first contrasted with self-reports of health. Then the temporal moments of the data are examined by considering the covariance structure of shocks that arrive at different ages with frailty in subsequent years. Then a formal model is estimated that incorporates both age-dependent auto-regressive and transitory components. The covariance structure of frailty is found to be convex in age. Larger shocks arrive as the sample ages but they decline rapidly. The evolutions of shocks beyond a specific age are modestly persistent (auto-regressive). The initial age-dependent transitory shocks become a larger portion of the total health risk as age increases.