[hellocs1]

Source on this?

the SAT of the 70s were much more of an IQ test than now. I'd be surprised if Kaplan prep could raise more than 20 or 30 points on average.

Also, having used Kaplan's prep material... They're pretty bad. But that was in the early 2010s for myself so they might have fallen in quality.

[JJMcJ]

Friend worked for Kaplan during the time period of the investigation.

IQ - you know IQ tests are renormed to reflect education levels, and raw scores mapped to give the bell curve?

So an IQ of 100 in 1900 would end up about 70 today. 70 oddly enough the number used to "prove" that people in the less developed world are inferior.