[ueqirat]

SAT prep has little effect on SAT scores. From research on this topic [1]:

"Does test preparation help improve student performance on the SAT and ACT? For students that have taken the test before and would like to boost their scores, coaching seems to help, but by a rather small amount. After controlling for group differences, the average coaching boost on the math section of the SAT is 14 to 15 points. The boost is smaller on the verbal section of the test, just 6 to 8 points. The combined effect of coaching on the SAT for the NELS sample is about 20 points. The effect of coaching is similar on comparable sections of the ACT. The average score increase on the ACT math section probably lies within the range of 0 to .4 points, while the coaching effect on the English section is about .3 to .6 points"

[1] http://nepc.colorado.edu/files/Briggs_Theeffectofadmissionst...

[36bydesign]

There is a lot of bad test prep out there, especially any test prep taught by high school teachers. I have done test prep privately for six years and I can guarantee you coaching can have substantial effects. These studies group all test prep under a giant umbrella, but take elite 1 to 1 test prep and the premium price it costs that parents actually pay and you'll see substantial gains. I have spend $0.00 on advertising in the last six years and I am routinely overbooked because of word of mouth. There's just so many awful teachers and courses out there.

[abeinstein]

Hm, it's very possible that SAT prep companies game the system by making their diagnostic tests quite difficult.