This report provides information about the performance of 1997 graduating seniors nationwide who took the American College Testing Program (ACT) Assessment as sophomores, juniors, or seniors. These students may not be representative of the total population of graduating seniors at a given school, depending on patterns of students taking the ACT. Average scores are reported for graduating seniors who completed a core high school program (typical college preparatory program) and for those who did not. The core program is defined as 4 or more years of English, 3 of more years of mathematics, 3 or more years of social studies, and 3 or more years of natural sciences. In general, those who complete a core program tend to earn higher average scores than students who do not. This association holds true without regard to ethnic group. In addition, the percentage of ACT-tested students who would be likely to receive at least a "B" in identified college courses is higher for those who completed the core curriculum. Over the last 5 years, the national average composite score for all graduates has increased from 20.7 to 21.0. African-American and Asian-American scores have remained stable while American Indian/Alaskan native scores have increased from 18.4 to 19.0. (Contains seven tables.) (SLD)