It is often proposed that high schools are partly to blame for the decline in achievement test scores. Critics of current practices in education cite the decline in Scholastic Aptitude Test (SAT) score averages that has occurred each year since 1963 as evidence. The College Entrance Examination Board Advisory Panel on SAT Score Decline has examined four areas for explanations of the decline: changes in the content of the SAT or errors in equating scores, changes in the testing population, changes in society, and changes in the schools. In this study, the curriculum, institutional, teacher and student factors associated with those schools having large decreases in SAT scores were compared with the same factors in schools with increasing or steady SAT score averages; identifying these factors might provide some insight into the role that school characteristics have played in the score decline. Although some significant differences between the two groups were found in terms of enrollments in academic courses, ability grouping, age of schools, dropout rate, and teacher experience, these do not explain a large portion of the decline. Indeed, differences among schools do not appear to have had large differential effects on the decline of scores. Data collection instruments are included. (Author/EVH)