"Why Rural Matters" is the fourth in a series of biennial reports analyzing the importance of rural education in each of the 50 states and calling attention to the urgency with which policymakers in each state should address rural education issues. The researchers framed this report around five gauges measuring: (1) the importance of rural education; (2) the level of socioeconomic challenges known to be barriers to academic achievement faced by rural schools; (3) the level of student diversity among rural students; (4) the rural educational policy context; and (5) the educational outcomes of rural students in each state. Each gauge is comprised of several equally weighted indicators--23 indicators in all--the largest number of indicators and gauges used by Rural Trust researchers to date. The higher the ranking on a gauge, the more important or the more urgent rural education matters are in that state. The authors combined the five gauge rankings, computing an overall ranking called the Rural Education Priority Gauge to prioritize states according to the overall status of rural education in each state. No state scores at the top on all five indicators, but the four highest priority states (Mississippi, Alabama, Arizona, and North Carolina) score the highest on four of them. States identified as the highest priority are ones whose rural schools face more substantial challenges than rural schools in other states, receive fewer resources than others, and produce less than others in terms of student educational outcomes. Poverty, fiscal incapacity, low levels of adult education, and low levels of student achievement run in the same mutually reinforcing circles in these states, many of which are as fiscally challenged as their citizens and schools. The states where rural education is most notably underperforming (that is, the state's performance ranks worse than its socioeconomic challenges would suggest it should) are predominantly non-rural states on the East or Westcoast where the rural population is "out of sight, out of mind," including, among others, California and Maryland. (Contains 279 figures, 262 tables, and 9 endnotes.)