This study is an extension of two previous studies that provided profiles of persisting STEM majors overall (regardless of academic performance) and persisting STEM majors who earned semester GPAs of 3.0 or higher (Westrick, 2016, 2017). Using data from 25 four-year institutions, this study compared the mean ACT assessment scores, HSGPAs, and ACT Interest Inventory scores between four groups of students: 1) those who persisted in a STEM field over eight semesters, 2) students who later joined the STEM field, 3) those who started in a STEM field but changed to another field, and 4) students who started in a STEM field but had departed their institution before the end of the fourth year. In this study more than 60 percent of the students who started as STEM majors changed majors or left school. While the students who persisted in or joined the STEM fields had higher mean ACT scores and HSGPAs than those for the students who left STEM fields or the institution, the four groups had similar measured interests.