As expected, there are significant differences between movers and non-movers (table 1). Students who never make a summer move are overwhelmingly enrolled in K–8 schools in fourth grade, disproportionately black (40 percent), poor (85 percent), and relatively low scoring (0.005 ELA and 0.020 math, grade 5; and 0.146 ELA and 0.132 math, grade 8), and those making only one summer move are almost entirely enrolled in K–5 or K–6 schools in fourth grade, disproportionately Asian (17 percent), white (14 percent), and high scoring (0.193 ELA and 0.262 math, grade 5; and 0.240 ELA and 0.226 math, grade 8).¹⁹ Furthermore, of the 66.2 percent of students who make only one summer move, the overwhelming majority make a structural move (87 percent) rather than a nonstructural move (13 percent). That is, students with relatively low levels of mobility appear less likely to make voluntary moves. Students making more than one summer move have characteristics associated with traditionally at-risk students: higher shares of black (34 percent), Hispanic (45 percent), and poor (84 percent) students, and lower performance on ELA and math exams in both fifth and eighth grades. Moreover, students who make two or more summer moves also make more mid-year moves than their peers who make zero or one summer move (0.30 compared with 0.13 and 0.09, respectively) and make roughly equal numbers of structural and nonstructural moves. Students who make at least one mid-year move are the lowest scoring of all groups (–0.031 ELA and –0.017 math, grade 5; and 0.025 ELA and –0.073 math, grade 8) and are disproportionately black (38 percent) and poor (86 percent). The majority of mid-year movers also experience at least one summer move during their academic careers (for relationship between summer and mid-year mobility, see table A.3 in the online appendix). Thus, movers and non-movers differ in in a variety of ways.