<p>If one looks at the annual datasets of the ACT or the SAT, there is a cumulative number of test takers reported, and then it's broken down by scores, and the number of test takers achieving that score. For example, in a given year the ACT might report 1,250,000 national test takers, and the number of test takers scoring a 29 might be something like 30,000. The dataset is generally reported as for the class of seniors entering college in that year, or similar language. This has always left me to wonder if the cumulative number is individual test takers, or the number of tests taken. For example, a given individual in the high school class of 2008 might have taken the ACT test as a junior and again as a high school senior. Does she count as 1 of the 1,250,000, or as 2? (Or, if she took the test only as a junior, does she count at all?) Or does the ACT or SAT only count the highest score of any individual who took the test numerous times in its cumulative datasets? If they didn't, wouldn't the percentile marks be necessarily misleading? (In other words, wouldn't the statement: "Your score places you in the 67th percentile of graduating seniors entering college" have to be amended to "...the X percentile of test results of all tests taken by members of this high school class?")</p>
<p>A somewhat related question: Is there any data breakdown available of how the same individuals scored if they took the standardized tests in different years of high school? (In other words, to show how multiple test takers tended to score as sophomores, juniors, seniors.) Or is there any dataset showing test results by high school year?</p>
<p>Thanks if anyone can explain or point me to this data.</p>