In the past I tried to use score pairing methods to equate the LSAT scores in Ron Hoeflin’s norming sample of the Mega Test, with IQs obtained on the Mega Test. One problem was that my I could only use about half the data since since LSAT scores were reported on two different scales. The 200 to 800 point scale used from before 1981 and the 48 point scale used from 1981 to 1991.
To solve this problem, I needed a way to convert from one scale to the other. Unlike the SAT there are apparently no tables converting older and newer versions of the test. Thus I converted scores on the 48 point scale to Z scores with respect to the LSAT population of that era. These were then multiplied by 105 and added to 530 (the approximate SD and mean, respectively, of the 800 point scale).
One problem with this method is it assumes the LSAT populations in both eras is comparable.
Table 1 shows the self-reported LSAT scores of all 13 individuals in Ron Hoeflin’s norming sample, along with their Mega scores:
When the 13 LSAT scores and 13 Mega scores are both placed in descending order, we get the following equivalencies:
Thus, a very rough formula equating pre-1981 LSAT scores to IQ (sigma 15) is IQ = 0.149116(LSAT) + 43.631712