The United States health care system is under tremendous pressure to cut costs while maintaining quality.

One mechanism to reduce costs is managed care-a system with both risks and benefits for patients, providers, and payors, and one that requires large volumes of data to ensure optimal medical and financial decisionmaking.

In this review, we describe the types of information needed by managed care systems, including medical outcome data (satisfaction, survival, quality of life, and complications) and financial data (costs and longterm resource utilization).

From a provider's point of view, the customers for these data range from individual patients to large self-insured corporations, and we describe the data required for each potential customer.

Finally, as a concrete example of how data can be collected and analyzed to improve a provider's competitiveness, we describe the Cedars-Sinai Medical Center cardiothoracic surgery database from a managed care perspective.

The concepts presented are generalizable to other subspecialties, and will become more important in the increasingly competitive milieu of American health care.