Pre-1974 SAT to IQ Conversion Table
The table is from the paper 'Conversion
Tables for Otis Gamma and Scholastic Aptitude Test,' by Warren W.
Willingham and James A. Strickland in the Personnel and Guidance
Journal, 41(4), 1962, 356-358. It took some effort and luck
to dig up this obscure paper. The experience was a bit like finding
a Rosetta stone. ;-)
Some things to note from the paper:
'The data are based upon a sample of 403 students who visited
the Office of Guidance and Testing at Georgia Institute of Technology during
the years of 1957-1960.'
In this group: Otis Gamma mean = 117, SD = 7.2; SAT mean = 980, SD =
'Equi-percentile Scaling: The line of relation between the
Otis Gamma and the SAT total score was plotted on the basis of 12 selected
percentile points. The line of relation was almost perfectly linear with
no evidence of abrupt curvature at either extreme. Table 1 shows
equivalent scores read from the smoothed line of relation. In no case
did the smoothing amount to more than one point on the Otis scale.'
'The correlation between the two scores was 0.58. The
standard error of estimate for the SAT total score was 102; the standard error
of estimate for the Otis was 5.8. This correlation of 0.58 gives a
spuriously low impression of the correlation between the SAT and the Otis due
to restriction in the range of ability in this sample.'
'The best interpretation of the IQ equivalents in Table 1 is
as follows: "This is the IQ John would achieve if he were to take the Otis
Gamma and do exactly as well (or poorly) as he did on the SAT." '
'Tables 1 and 2 should not be extrapolated
beyond the values presented. It is virtually certain that the line of
relation and the regression line are not linear throughout the range of
possible scores. In fact, it is probable that abrupt curvature sets in a
score levels higher and lower than those included here.' Based on
high-IQ society entrance criteria, this seems to be true. The line would
abruptly curve up at the higher end. Note that the Mensa criteria of a SAT score of 1250 being equivalent to an IQ of
132 is quite consistent with the table below. If someone knows why
they have 1300 for scores before 1974, please send an email
to enlighten me. Otherwise, I'd consider this table valid for scores before 1974 and
after (until the re-centering of 1995).
Equivalent Scores for Otis Gamma and Scholastic Aptitute
Test Total Score
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