The current study aimed to contribute to a deeper understanding of the organizational conditions of charter schools by examining teacher turnover. Using data from the National Center for Education Statistics (NCES) 2003-04 Schools and Staffing Survey (SASS) and the Teacher Follow-Up Survey (TFS), researchers from the National Center on School Choice looked at how teacher turnover differs between charter and traditional public schools and the extent to which these differences are explained by variations in teacher characteristics, school organizational conditions, and contextual factors such as demographic characteristics. In addition, the study examined how turnover varies within the charter school sector. Central questions of the study were: (1) How does the rate of teacher turnover differ between charter schools and traditional public schools?; (2) How do teacher turnover rates vary within the charter school universe, and which types of charter schools have higher/lower turnover rates?; (3) To what extent are the differences in turnover rates between charter schools and traditional public schools explained by differences in teacher characteristics?; (4) To what extent are the differences in turnover rates between charter schools and traditional public schools explained by differences in organizational conditions and contextual factors?; and (5) What reasons do charter school teachers give for leaving the profession or moving between schools, and how do these reasons differ from those given by traditional public school teachers? The study ultimately was interested in the relationship between school sector (charter school and traditional public school) and teacher turnover (attrition and mobility). Researchers hypothesized that the difference in turnover between sectors ("the turnover gap") was due partly to systematic differences in the characteristics of charter and traditional public school teachers. They also hypothesized that the turnover gap was due partly to differences in the organizational conditions of charter schools and traditional public schools, which may stem from charter schools' autonomy from many of the rules and regulations that govern traditional public schools. In addition, they expected turnover to be affected by the context of the school. Key findings include: (1) The rate that teachers leave the profession and move between schools is significantly higher in charter schools than in traditional public schools; (2) Charter schools that are started from the ground up experience significantly more attrition and mobility than those converted from traditional public schools; (3) Differences in teacher characteristics explain a large portion of the turnover gap among charter and traditional public school teachers; (4) Dissatisfaction with working conditions is an important reason why charter school teachers are significantly more likely to switch schools or leave the profession; and (5) Involuntary attrition is significantly higher in charter schools. (Contains 5 footnotes.)