"[C]onsumer-directed health plans ... combine a high deductible with a tax-advantaged personal health account whose funds roll over from year to year. In exchange for the high deductible, monthly premiums are reduced.... In 2011, about 17 percent of Americans with employer-sponsored health coverage were enrolled in a consumer-directed plan. A 2012 survey found that 59 percent of large employers offered at least one such plan.... [This report describes the results of] a series of studies to examine the effects of high-deductible plans -- particularly consumer-directed plans -- on the costs and use of care."