This study of the persistence behavior of undergraduates at America's 4-year colleges and universities used data from the "High School and Beyond" study, a national survey of 28,000 high-school seniors. "Persistence" is described as the flow of students through college over a 6-year period. Four categories of persistence were identified--completers (those who completed a bachelor's degree), persisters (those who were continuously enrolled), stopouts (those who left and returned), and dropouts (those who left and did not return). Findings of the study include: (1) degree completion was lower than anticipated from a review of literature; (2) completion was more timely and at a higher rate in independent colleges and universities than at public institutions; (3) Black and Hispanic completion rates lag seriously behind those of whites and Asian Americans; (4) the greatest enrollment loss occurred during the first year and after the eighth semester; (5) both socioeconomic status and academic ability influence persistence; (6) the cumulative effect of socioeconomic status and ability is greater than the influence of either factor by itself; and (7) students who received grants in their first year of study were more likely to remain enrolled than students without grants. Includes 40 references. (JDD)