A sharp decline in the number of Scholastic Aptitude Test (SAT) candidates scoring over 600 (on a scale of 200-800), has been observed from 1969-70 through 1974-75. Several suggested explanations of this phenomenon relating to test-taking patterns are discussed. Specifically examined are the possibilities that fewer students take the SAT more than once, that fewer students take the Preliminary Scholastic Aptitude Test before the SAT, or that fewer high-scoring students take both the SAT and the ACT (American College Testing Program) battery. These factors might account for part of the observed declines. Although ideal data for testing all these explanations were not available, certain data suggest that while changes in test-taking patterns may have had some effect, they probably cannot entirely explain the downward trend in SAT score averages. (Author/EVH)