In this chapter, the author examines estimates of the extent of STEM switching and relocation at the national and institutional levels drawing on evidence from national survey sources and from institutional records provided by the six institutions participating in the study. The institutional records analysis points to variations in types of switchers. It also yields rates of switching and persistence by institutions, disciplines, gender, race/ethnicity, first-generation student status, and quartiles of highest-to-lowest blocks of mathematics scores and GPAs. Analysis by combinations of these variables offers a more accurate picture of which groups switch than analysis of groups in isolation. Comparison of students in the highest and lowest quartiles of cumulative GPAs before switching also yielded contrasts between these student groups in terms of their choices of initial and destination majors, gender, and URM status. As in the original study, the vulnerability of high-performing women to switching was revealed in the institutional records analysis with women in under-represented minority groups at greater risk of switching than white women and all men. This chapter also describes the most populous pathways of switchers into non-STEM majors, with variations by initial majors, gender, race/ethnicity, and GPA. It draws attention to a strong trend among switchers from all disciplines to move into undeclared majors. This chapter ends with a discussion of findings about the timing of students’ moves out of their initial STEM majors.