Accountable Care Organizations (ACOs) are the latest attempts by payers, particularly the Centers for Medicare and Medicaid Services (CMS), to curtail the growth in healthcare spending and improve outcomes. This article from Government Health IT discusses the recent CMS ruling on updating the Medicare Shared Savings Program (MSSP).  This article from Health Affairs Blog, dated from mid-2014, discusses some of the preliminary financial results of MSSP as well as Pioneer ACO, both Medicare-related, as well as some early Medicaid and commercial initiatives. ACOs will continue to play a role in the healthcare delivery and understanding them will be crucial to those involved with the industry.