Accessibility and the demand for preventive care

The multifaceted nature of accessibility poses the problem for health care policy research of determining those types of access barriers which are most important. Following the suggestion by Aday and Andersen, we approach this problem by means of external validation, i.e. by empirical analysis of the role of different types of access barriers in determining whether or not individuals obtain care. Specifically, we estimate the effect of access barriers on the probability of obtaining a physical examination. The application of the basic economic demand model to the case of preventive services is discussed and several extensions of the basic model are suggested. Then multiple regression analysis is applied to household interview data from Baltimore, Velmont, and Saskatchewan to obtain physical examination demand functions. Our results provide some support for the predictions of the economic model concerning the effect of financial and physical access barriers on demand. But the fact that education, attitudes, and relationship to a regular source of care are the most consistently significant determinants of demand suggests that the current policy emphasis on financial and physical access barriers may be too narrow.