The economic and medical consequences of noncompliance to the U.S. health care system are examined in this 32-page NPC publication. The Task Force for Compliance shows that when patients fail to adhere to prescribed therapies, they fail to improve, worsen or relapse. The costs of addressing ensuing health complications is enormous, and accounts for up to $100 billion in health care and productivity costs. The authors note that the workplace productivity losses are largely hidden. The paper explores the dynamic that exists between patients and physicians, and how this dynamic can lend to non-compliance. One key manifestation of non-compliance is prescriptions that go unfilled. Authors explore drivers behind this patient behavior, as well as compliance-improving strategies, and note that physicians, pharmacists, managed care organizations, and, ultimately, patients are key in improving compliance.