about estimating the costs of illness has centered around the relative advantages and disadvantages of the two basic methodologies used or proposed-the "human capital" method as against "willingness to pay." Very briefly, the human capital approach requires estimating the direct costs of illness, i.e., the costs of prevention, detection, treatment, and rehabilitation, as well as the indirect costs to society due to lost earnings resulting from morbidity and premature mortality. Willingness-to-pay estimates, by contrast, are based on the amounts persons would be willing to pay to reduce their risk of incurring, or dying from, a given disease or diseases. Although this latter approach is more satisfactory on theoretical grounds, lack of appropriate data has so far limited its use in practice, and most estimates of the costs of illness made to date have used the