More graduating seniors took the SAT last year than ever, 1.65 million. So why are the scores declining, and why is the best-known and most fearsome college-entrance test in U.S. history losing its edge?

Let’s start with the obvious. More students are taking its rival, the ACT. As my colleague Michael Alison Chandler reported, the SAT still dominates in the Washington area and on the East and West coasts. But more students, including those in the Washington area, are turning to the ACT when they bomb on the SAT, which contributes to the drop in average SAT scores. Low scorers took their usually better re-test score to the ACT.

The SAT has less power now to get students into the most selective colleges. Competition for the hottest schools has become so intense, with acceptance rates dropping below 10 percent, that a score of 2100 to 2400 gets you into only the maybe pile. Depending on your extracurricular activities, recommendations and family background, you might get in. Rejected and accepted applicants often look no different than Tweedledum and Tweedledee. And hundreds of schools, even some selective ones, let you apply without an SAT or ACT score.

The people who try to predict district- and school-level SAT averages are also frantic because the mix of students whose scores are counted keeps changing. As Chandler reported, the College Board for the first time added 50,000 scores from students who took the SAT after March of their senior year. That is a sign of desperation and of poor performance. As more students try college, many more lower-achieving students are taking the test.

This has created so much confusion that some standardized test critics, such as FairTest spokesman Bob Schaeffer and my colleague Valerie Strauss, are accepting SAT results as meaningful after years of doing the opposite. They say the SAT score decline shows that federal and state school improvement measures have failed. When SAT doubters such as them start taking the test’s scores as reliable measures, you have to assume something has gone haywire. (Schaeffer and Strauss both reject my analysis of their arguments.)

The SAT is not a suitable measure of school reform, but there are two things it is good for. It helps above-average (but not straight-A) students find ways to anchor themselves in the topsy-turvy college admissions world. For instance, a student in a competitive high school can use her SAT score as proof to admissions officers that she has attained an academic level comparable to that of an applicant with the same score but higher grade-point average at Grade Inflation High School.

Also, because SAT scores still matter for students applying to colleges that are selective but not near-impossible like the Ivy League, their SAT score becomes a good indicator of which college is most likely to accept them. Students can look up the SAT scores of freshmen accepted in previous years for almost every U.S. college. Find the colleges that select students with scores similar to theirs, and then decide which of them have the academic and extracurricular strengths they want. That leads to good results with less stress.

Despite its flaws, the SAT will be with us for years to come. Do your best on the test, then forget about it. It will soon be out of your life.

A few people such as me can still remember our scores. We talk as if the experience was a horror, when actually it was a thrill. Pity us, and be assured that by the time you get to be my age, no one will ask you your score, even when you wish they would.