Data from the fifteen Hospital Regions of England and Wales were used to determine the utility of health outcome indexes, derived from existing health statistics, for monitoring the quality and effectiveness of health services. Outcome measures reflect not only the impact of the system of care but also the sociodemographic characteristics of the population. An attempt therefore was made to identify those outcome measures most sensitive to variations in medical care and least affected by sociodemographic differences. In general, most indexes examined in this paper appear to be more sensitive to variations in the sociodemographic characteristics of the population. However, those outcome measures related to provision of care in hospital appear to be relatively more sensitive to variation in medical care than those which are community based. This suggests that, at least for monitoring the effectiveness of medical care in the community, it may be necessary to move away from the more “traditional” health indexes toward measures that take into consideration the different patterns of care and the social and behavioral aspects of health.