Education decision makers in Colorado, Missouri, and South Dakota share concerns about and need more information on changes in school and district leadership (principals, assistant principals, superintendents, and assistant superintendents), including mobility (when leaders move to a different school or district within the state public school system) and attrition (when leaders stop serving in a leadership position in the state public school system). In collaboration with educators in those states, the Regional Educational Laboratory Central used administrative data for 2015/16 to 2018/19 to identify the percentages of school and district leaders who remained in a leadership position in the same school or district (stayers), who transferred to a leadership position in a different school or district (movers), and who took a nonleadership position or left the state public school system (leavers) after one year and after three years. The study also examined the characteristics of principals, schools, and districts that were associated with principal mobility and attrition. Across the three states the percentage of school and district leaders who were stayers ranged from 77 percent to 82 percent after one year and from 51 percent to 56 percent after three years. After three years younger principals were more likely to be a mover than a stayer, and older principals were more likely to be a leaver than a stayer. Principals who identified as a racial/ethnic minority and those who earned a lower salary were also more likely to be a mover or a leaver. In addition, principals were more likely to move from or leave low-performing schools that the state identified as needing additional support for improvement and schools in lower-performing districts (districts with lower average student academic achievement). The findings suggest that decision makers may wish to better understand the causes of school leader mobility and attrition and enhance supports for younger principals, principals who identify as a racial/ethnic minority, and principals in low-performing schools. [For the full report, see ED607378; for the appendixes, see ED607379; and for the study snapshot, see ED607382.]