Should you take a course to prepare for the SAT*? Let's look at 12 different factors....just kidding. No. The answer is no. With very few exceptions which I'll explain at the bottom, you shouldn't bother with a prep course.
You especially don't want to take a test prep course before you've taken a test. It's quite common to take a practice PSAT in the 9th and/or 10th grade (because who doesn't like practice tests for the practice test?). So you likely have some starting test scores. But if you don't, wait until you've got PSAT or SAT scores before even thinking about taking a test prep course. It's just not generally wise to start fixing a problem until you know you've got the problem.
But let's say you've taken a PSAT in the 9th, 10th, or 11th grade, and you're unhappy with your scores. Should you take a test prep course to help you improve them? No.
Even if it works, it's probably not worth the time and money. Let's say that you could raise your SAT score 50 points by doing well in a prep course. 50 points! That's a lot! Eh, maybe. It sounds like a lot, because the SAT is scored on a weird and arbitrary 1600-point scale...that changes every few years...and is sometimes a 2400 point scale. Which means we don't really know what those 50 points mean. So instead, convert them into a type of number that you intuitively understand and are used to dealing with: percent.
Look at how those 50 points affect your percentile score. The percentile score tells you how you did on the particular test compared to everyone else who took that test. So if you scored in the 86th percentile, that means you scored the same or better than 86 percent of people who took the same test. Or, if you prefer, you did better than 86% of your competition. When you look at percentiles, you can see how much a difference that 50 points makes relative to everyone else.
So let's start with a 1000 combined score on the 2016 SAT. According the the College Board guide to understanding your scores, that means you scored in the 48th percentile. 50 more points--1050--puts you in the 58th percentile. That seems significant, and maybe you'll decide it's significant enough to take a prep course. But if your scores are likely to go from "barely in the bottom half" to "slightly in the upper half," ask yourself if the cost in time and money is really where you need to be spending your resources preparing for college.
The difference between 1100 and 1150 is 67th to 74th percentile. The difference between 1200 and 1250 is 81st percentile to 86th. The difference between 1300 and 1350 is 91st to 94th percentile. The difference between 1500 and 1550 is 99th percentile to "99+ percentile," whatever that means. The higher you go, the less those 50 points are really going to seem significant. If you got a 91 on a test for a class, and your teacher said that if you did a whole lot of extra work you might get it up to a 94, would you bother? Probably not; you'd take the A and spend your time on something else.
When it gets down to it, your SAT score only matters for a few months. Your 12th grade SAT scores are tied to college admission and nothing else. You're very unlikely to talk to anyone about the SAT, much less discuss your scores, once you're on a college campus. As soon as you start college, they're as important as the clothes you wore under your gown to high school graduation. Hardly anybody saw them, and even fewer care.
Opportunity cost. Virtually everything else you might do to prepare for college applications will have a benefit that lasts longer and is more important. Take a more rigorous elective class and do well at it, design and implement a research project, spend more time working for your after-school club so that you become a leader, audition for a play, volunteer more in your community, get a job, read more novels, learn to play a musical instrument, take a meditation class....Any of these things can help you with college applications AND be useful to you after you graduate high school. Any of these things might help you become a more productive, happy, or interesting person. I've never heard any one credit a test prep course for making them a better person. A test prep course is just too big an investment for too little return, even when it does what it's supposed to do. While higher SAT scores will indeed make for a better resume, any other productive thing you'd do will make for a better person.
With all that said, I can still think of a few reasons why you may still want to take a prep course.
1. You want it for the course content, not raising test scores. Maybe your Geometry teacher left in the middle of the year and you had a sub who wasn't so great. You got good grades, but didn't really learn Geometry. Re-taking the course seems tedious, and teaching yourself math seems daunting. Maybe going to a test prep course for a review in high school math is a good way to get quality help. Similarly, if you're not a strong reader and think some targeted vocabulary work and reading strategies might help, then a test prep course might also be a good way to go. So you might end up taking a test prep course for reasons other than simply boosting your SAT score, and it may have the added benefit of boosting your score.
2. Social exposure. I don't mean a chance to hang out with your friends more often or find dates. I mean if you're a home-schooled teenager, go to a very small school, or are otherwise isolated, then a test prep course might be a way for you to get more exposure to groups of peers before heading off to college. Because it's academic and limited to people your own age, it might be more palatable to you or your family than other forms of branching out. Again, the possible boost in test scores is a bonus, not the main attraction.
3. You have to take it anyway. Maybe your school put you into a test prep class, or maybe your parents made you sign up for a prep course against your will. By all means, do your best and get what you can out of it. Don't blow it off just because I said not to take one. Make the most of where you are.
4. Psychic scars. You didn't make it into the Gifted & Talented program because your test scored were just below the cutoff. Or you once failed a class because you got a 69.4 and you needed a a 70. Maybe your scores on a preliminary test were just below the cut-off for National Merit qualification. And now you're dedicated to never making that mistake again; you'll always reach for the extra few points. I understand. I'm not going to argue against that. There are certainly worse ways to cope with those scars.
If you can think of another really good reason to take a test prep course that I'm missing, leave me a comment. If you enjoyed this post, please share it with someone you think will enjoy it.
*I'm more used to the SAT than the ACT, and it's still the more popular test. If you're an ACT person--all this applies to you, too.
[Full disclosure: I took a test prep course in high school. It wasn't one of the big-name commercial ones, just one my school district offered for free in the summer. I kind of liked it. I don't think it helped my test scores at all.]