The article by John E. Wennberg and Alan Gittelsohn examines the variations in health care delivery across small areas, particularly in Vermont. The authors highlight the importance of population-based health information systems in guiding planning and regulatory decisions. They discuss how recent legislation has expanded the authority to regulate health care facilities and services, influencing factors such as expenditures, facilities, and manpower. The study focuses on Vermont, where a data system monitors health care delivery in 251 towns, revealing significant variations in resource input, utilization, and expenditures among different areas. These variations suggest uncertainties in the effectiveness of different levels of health services and highlight the need for more detailed and population-based data to inform regulatory decisions. The authors argue that population-based health information systems are crucial for developing rational public policy in health care.The article by John E. Wennberg and Alan Gittelsohn examines the variations in health care delivery across small areas, particularly in Vermont. The authors highlight the importance of population-based health information systems in guiding planning and regulatory decisions. They discuss how recent legislation has expanded the authority to regulate health care facilities and services, influencing factors such as expenditures, facilities, and manpower. The study focuses on Vermont, where a data system monitors health care delivery in 251 towns, revealing significant variations in resource input, utilization, and expenditures among different areas. These variations suggest uncertainties in the effectiveness of different levels of health services and highlight the need for more detailed and population-based data to inform regulatory decisions. The authors argue that population-based health information systems are crucial for developing rational public policy in health care.