Assisted living exemplifies the shift from "care as service" to "care as business" in the broader health care arena predicted more than three decades ago. A consumer-driven industry, assisted living offers a wide range of options, levels of care, and diversity of services (Lockhart, 2009) and is subject to state rather than federal regulatory oversight. What "Assisted living" means depends on both the state and provider in question: variations in state regulatory definitions are significant and provider variables include everything from philosophy, geographic location and auspice, to organizational size and structure. Assisted living evolved from small "board and care" or "personal care" homes and offers a "social model" of care (compared to the medical model of a skilled nursing facility). The assisted living industry is a segment of the senior housing industry and assisted living services can be delivered in stand-alone facilities or as part of multi-level senior living community. The industry is fragmented and dominated by for-profit providers. In 2010, six of the seventy largest providers were non-profit and none of the top twenty was non-profit (Martin, 2010). Information in this edit is from an article published in 2012 that reviewed the industry and reports results of a research study of assisted living facilities.