By the turn of the 21st century, several factors gave rise to concerns about a shortage of primary care in the United States . From an aging generation of baby boomers to increasing numbers of physician retirees, it was projected that the United States would be short about 40,000-52,000 physicians by the 2020s. Furthermore, "implementation of the Affordable Care Act identifies millions of newly insured patients needing primary care." This shortage was viewed by many as an opportunity to expand the scope of practice of existing healthcare professionals, such as pharmacists.