<p>They recentered the SAT in the mid 90’s because the average score was dropping so much below 1000. The effect of the recentering is that a “normal” score has 100 points added to it. Scores in the 1970’s were never low. The recentering was done because they were higher in the 1970’s, and they gave everybody taking it now a bonus. (The details of the recentering algorithm are rather complex, but the average bonus was 100 points.) Also, nothing kept people from prepping for it or taking it multiple times. Most people did not, however.</p>
<p>The requirement for Mensa is that you score in the top 2% of some test that measures IQ. At any rate, Mensa no longer accepts the SAT as one of the acceptable tests since they decided that it doesn’t measure IQ.</p>