Georgia’s certificate-of-need law regulates the construction of hospitals and the provision of new or different health services. The dispute concerned whether a certificate authorized Windy Hill Hospital to change from long-term care to short-term acute care and whether applying the requirement would violate the constitutional prohibition on retroactive laws. The Supreme Court of Georgia first addressed whether a certificate creates a private or public right and how the Department of Community Health’s regulations should be interpreted. The Court clarified the governing framework and remanded for further proceedings consistent with its interpretation, leaving the ultimate certificate-of-need and retroactivity questions to be resolved under that framework.