Why is National Merit Scholar award based on PSAT instead of SAT?

[BobWallace]

This is quite different than when I went to high school and kids took the PSAT in their junior year cold and the SAT in their senior year cold without any studying or prep course.

I graduated high school in 1981, and we took the PSAT in sophomore year to prep for the “real” PSAT in junior year. I also had many peers who took SAT prep courses, although I personally did not.