Descriptions of Extra Variables for Propensity Scores.

Variable	Description
Adolescent Factors
Grade point average	NCES-constructed measure based on adolescents' 1988 reports of grades in math, science, English, and social studies. This measure takes the form of a standard four point grade point average (M = 2.98, SD = .73).
Locus of control	NCES-constructed measure based on the mean of adolescents' 1988 responses (1 = strongly agree to 4 = strongly disagree) to five items, including “”I don't have enough control over the direction my life is taking” (M = .05, SD = .71). Constituent items were standardized.
Positive self-concept	NCES-constructed measure based on the mean of adolescents' 1988 responses (1 = strongly agree to 4 = strongly disagree) to five items, including “On the whole, I am satisfied with myself” (M = .02, SD = .73). Constituent items were reverse-coded and standardized.
Timing of immigration	In 1988, parents reported when an adolescent born outside the U.S. came to the U.S. Reports were dichotomized into less than five years (1%) or more.
Middle school athletic participation	Adolescent reported involvement with varsity sports in 1988 (57%).
High school athletic participation	Adolescent reported involvement with any of 30 school clubs and extracurricular activities in 1990 (75%).
Middle school activity participation	Adolescent reported involvement with any of 7 school sports in 1988 (51%).
High school activity participation	Adolescent reported involvement with any of 11 school clubs and extracurricular activities in 1990 (61%).
Expectations for high school	Adolescent reported whether they expected to enroll in college-preparatory program in high school (33%).
Future educational expectations	Adolescent reported how far he/she expected to get in the educational system (1 = won't finish high school, 2 = will finish high school, 3 = vocational school, 4 = attend college, 5 = graduate from college, 6 = enter higher school after college) (M = 4.68, SD = 1.23).
Parent/Family Factors
Home language use	NCES-constructed measure, based on adolescent and parent interviews, dichotomized into non-English is primary/sole language (12%) or not.
Parent discussion of coursework	In 1988, adolescents reported how often (1 = never to 3 = often) they talked with their parents about course selection (M = 2.50, SD = .50).
Parent school-based involvement	Sum of adolescents' 1988 reports of whether their parents had attended a school event, spoken with their teacher, visited their classes, or attended a school event (M = 1.90, SD = 1.23).
Extended family structure typology	NCES family structure composite extended to include categories for two-parent (65%), single parent (16%), stepparent (11%), and other family.
Middle School Factors
Size	NCES composite based on 1988 school administrator reports, with categories ranging from 1 (1-99 students) to 7 (1200+) (M = 3.75, SD = 1.76).
% race/ethnic minority students	School administrator reports of percentage of non-Whites in student body (M = 24.27; SD = 28.03).
% students on free/reduced lunch	School administrator reports of percentage of student body receiving free and reduced lunches (M = 22.28; SD = 21.93).
Math/science instruction requirements	School administrator reports of whether full-year instruction in math and science required for all 8th graders in school (M = .86, SD = .34).
Non-English math/science instruction	1988 school administrator reports of whether non-English math and science instruction was available in school (M = .04, SD = .20).
Mode of course assignment	Four variables, based on 1988 school administrator reports of how much influence (1 = none, 4 = a lot) parents (M = 2.12, SD = .82), teachers (M = 2.38, SD = .71), counselors (M = 2.13, SD = .89), and test scores (M = 2.40, SD = .80) had in the assignment and/or selection of high school courses/programs for eighth grade students.
High School Factors
Size	See middle school description (M = 4.71, SD = 2.40).
% race/ethnic minority students	See middle school description (M = 27.05; SD = 26.69).
% students on free/reduced lunch	See middle school description (M = 19.09; SD = 19.67).
Grade structure	Whether school contained an eighth grade (18%) or not, based on school administrator reports.
Number of math/science teachers	School administrators' estimates of how many teachers they had in various departments, ranging from 0 (0-5) to 3 (15+). The sum for math and science was taken (M = 2.20, SD = 1.76)
Math/science course offerings	Proportion of 16 math courses and 17 science courses offered in school, based on responses of school administrator to a set list of courses in each subject (M = .59, SD = .11).
Mode of course assignment	See middle school description (M = 2.12, SD = .82 for parents, M = 2.38, SD = .71 teachers; M = 2.13, SD = .89 for counselors, M = 2.40, SD = .80 for test scores).

Note: All Sociodemographic and school controls also included in propensity scores.