Effects of Differential Prediction in College Admissions for Traditional- and Nontraditional-Aged Students

A C T Rese&rclk R eport Series 2 0 0 0 -9Effects of Differential Prediction in College Admissions for Traditional and Nontraditional-Aged StudentsJulie NobleSCTJuly 2000 For additional copies write:ACT Research Report Series PO Box 168Iowa City, Iowa 52243-0168© 2000 by ACT, Inc. All rights reserved. Effects of Differential Prediction in College Admissions for Traditional- and Nontraditional-Aged StudentsJulie Noble AbstractThis study determined whether using ACT Composite score, high school grade average, or both predictors jointly for college admissions would result in differential prediction or differential outcomes for traditional-aged and nontraditional-aged students. The analyses were based on data from 112,341 students at 79 postsecondary institutions.Both total-group and within-age group regression models were estimated by institution. Linear regression models were used to predict students' first-year college grade average. Corresponding logistic regression models predicted students’ chances of a 2.5 or higher, or 3.0 or higher, GPA. Validity statistics were calculated for each model, by institution, and then summarized across institutions. The results for the total-group and within-group models and optimal cutoffs were then compared.The total-group ACT Composite and high school grade average models slightly overpredicted the first-year GPAs of nontraditional-aged students, and they underpredicted the GPAs of traditional-aged students. When used jointly as predictors, virtually no differential prediction or differential effects were found for the two age groups. Effects of Differential Prediction in College Admissions for Traditional- and Nontraditional-Aged StudentsIn recent years, the percentage of non traditional students enrolled in college has increased. As defined by the National Center for Education Statistics (NCES; 1996), nontraditional students include those students with one or more of the following characteristics: did not enroll in postsecondary education for at least one year after high school, part-time enrollment, financially independent, worked full-time while in college, had dependents, was a single parent, or did not have a standard high school diploma. Between 1986 and 1992 the percentage of “moderately” nontraditional college students (delayed college enrollment, part-time, and financially independent) increased from one in four undergraduates to nearly one in three undergraduates (NCES, 1996).An important characteristic of nontraditional students is their age. Among “moderately” and “highly” nontraditional undergraduates (students with four or more nontraditional characteristics), 89% to 99% were older than was the typical undergraduate, while 38% to 48% of “minimally” nontraditional students (one nontraditional characteristic) were older. All other characteristics aside, enrollment of older undergraduates alone increased from 54% of all undergraduates to 59% between 1986 and 1992.In general, nontraditional students are concentrated in two-year colleges (e.g., 62% of undergraduates of age 30 or more enroll in two-year colleges, as compared to 38% of students of 23 or younger; NCES, 1995). However, the increase in nontraditional undergraduates has not been limited to two-year colleges: Between 1986 and 1992 four-year public institutions saw an increase in nontraditional students from 31% to 39%; four-year private institutions saw an increase from 15% to 22% (NCES, 1996). With the increase in the number of nontraditional-aged students enrolling in college, one concern, particularly of four-year colleges, is the appropriate standards to use in admitting these students. Are the standards used for traditional-aged college students (i.e., high school grades, standardized test scores) appropriate for nontraditional students? Given the varying time delays between high school and college, high school grades might not accurately reflect students’ current knowledge and skills. Two studies (Levitz, 1982; Breland, Maxey, McLure, Valiga, Boatwright, Ganley, & Jenkins, 1995) showed that institutions tend to make admission decisions for nontraditional-aged students differently from those for traditional-aged students. For example, Levitz found that private two-year, and public and private doctoral degree granting institutions were more likely than other types of institutions to require nontraditional-aged students to have standardized test scores for admission. However, selective institutions were more than two times as likely to require test scores for traditional-aged students than for nontraditional-aged students.Research seems to support using differential