The official in charge of Medicare and Medicaid for the last 17 months says that 20% to 30% of health spending is "waste" that yields no benefit to patients, and that some of the needless spending is a result of onerous, archaic regulations enforced by his agency. The official, Dr. Donald M. Berwick, listed five reasons for what he described as the "extremely high level of waste." They are overtreatment of patients, the failure to coordinate care, the administrative complexity of the health care system, burdensome rules and fraud. "Much is done that does not help patients at all," Berwick said, "and many physicians know it." In an interview on Thursday, his last day on the job, Berwick reflected on his successes, failures and frustrations in trying to engineer a rapid transformation of the healthcare system while beating back criticism from Republicans in Congress.