These vignettes are fiction. Yet, every day, across the nation, these and similar scenarios play out and each describes a valid and legitimate need for medical information. Sometimes the questions are answered quickly and correctly. Sometimes they are not, especially when no central repository of information or network of data sources exists or can be queried easily. In response to this situation, many experts in the health care field share an exciting vision: a community-oriented database or group of linked databases that can address all kinds of inquiries about health care matters in a timely and satisfactory manner.

This report from an Institute of Medicine (IOM) study committee examines the potential that existing and emerging health databases offer for fulfilling this vision. It gives special attention to appropriate uses of data in such repositories and to adequate protections for the privacy and confidentiality of individually identifiable information. It concludes that "health database organizations" can play a pivotal role in health care delivery and research but that they, or other interested parties, will have to take significant steps to ensure that private information remains private. To promote these ends, the committee advances recommendations that are detailed in subsequent chapters. Taken together, the committee's findings, conclusions, and recommendations underscore the extreme importance of the ways in which health care information is to be controlled and used in the future. 

The desire to understand and improve the performance of the health care system begets a need for data to answer the questions that opened this report. This, in turn, motivates proposals for the creation and maintenance of comprehensive, population-based health care databases that can provide such information with ease and reliability. The past quarter-century has already seen an exponential rise in the number, complexity, and sophistication of health databases, yet they do not approach in extent, inclusiveness, or quality the vision offered above.

What is the state of health databases today? The databases briefly noted here illustrate the range of existing databases; Chapter 2 discusses selected databases in more detail. Among the oldest and best known of the so-called administrative data sets are those associated with the Medicare program, particularly the Part A and Part B files (for, respectively, inpatient and outpatient services) and more recent compilations such as the National Claims History system. All states maintain some form of database for their Medicaid programs; more than two-thirds maintain databases on hospital