This policy brief: (1) contrasts the proportion of math and science teachers who leave STEM fields within one year, three years, five years, and ten years with the proportion of English or Social Studies teachers who turnover during these intervals (2) examines stability of the year-to-year turnover from STEM fields (3) describes how teachers who leave math or science teaching assignments move into other STEM assignments, to non-STEM assignments, or leave the public schools of Missouri entirely, and (4) describes the rates at which teachers who are still teaching in STEM fields remain in the same school and district, shift to a different school in the same district, and shift to a different school and district. 5) contrasts the instability of STEM teachers in the five largest cities of Missouri with the instability of STEM teachers in the rest of the state.