This report aims to pinpoint the cause(s) of spiraling tuition by taking a deep dive into public university revenue and spending data from the National Center for Education Statistics’ Delta Cost Project Database. The authors split public 4-year universities into two categories: research institutions—schools that have a high level of research activity and award a significant number of doctorates—and master’s and bachelor’s universities—schools that primarily award master’s and/or bachelor’s degrees. They found that declining state appropriations for higher education is indeed the primary driver of rising tuition, responsible for 79 percent of tuition hikes at public research universities between 2001 and 2011 and 78 percent of tuition hikes at public master’s and bachelor’s universities over the same decade.