The potential impact of cohort changes with regard to ethnic group, gender, class rank, and first language learned on yearly average Scholastic Aptitude Test (SAT) and Test of Standard Written English (TSWE) scores was studied. Regression and cross-classification analyses were conducted on data from 1985, and 1987 to 1990. Both analyses adjusted test score means based on common cohorts of students. The analyses indicated that approximately half of the decline in SAT verbal (SAT-V) scores was associated with cohort change. Average SAT mathematics (SAT-M) scores could possibly have risen by three points, rather than remaining constant, if the 1987 and 1990 cohorts were the same. (29pp.)