<p>^No, the curve is not made before the test is administered. As mentioned in the reference you gave, when a new form (a new version of the SAT) is administered, student performance on old tests and the current new test is compared by using identical test sections (these are the equating / ungraded sections). This can’t be done until the test is actually administered. Some SATs were previously administered; for these, the curve is known ahead of time.</p>
<p>The curve depends only on the difficulty of the scored sections of the new test, not on the performance of those taking it.</p>