Official Historical SAT to IQ Conversions
These data were combined from two hard-to-obtain sources. The first was
A
Study of Error: a Summary and Evaluation of Methods Used in Six Years of
Study of the Scholastic Aptitude Test of the College Entrance Examination
Board by Carl C. Brigham, Associate Secretary of the College Entrance
Examination Board (1932). The second was the
Otis Self-Administering
Tests of Mental Ability (Higher
Examination, Form A) IQ Scales (1922-1928). Only raw scores were provided in the first source so the second source was needed to get the corresponding IQ scores. The following two paragraphs are a direct quote from the Study of Error, p.336:
It would be expected that a test designed for use in high schools
would not differentiate the upper range of college applicants and this
proved to be the case, although this is not a reflection upon the Otis
test. 1080 candidates were given the Otis test with a half-hour time limit.
The mean scholastic aptitude score of these candidates (randomly sampled)
was 499.213 and the sigma was 99.272. The mean Otis score was 58.7435,
sigma 8.6839. The correlation between the two examinations was .7931. As
the maximum possible score on the Otis examination was 75, the distribution
of Otis scores was cut off sharply at the upper end and high score candidates
probably were not completely differentiated.
Table XVIII gives the most probable scholastic aptitude
test score, percentile, and letter grade for each Otis total score. The Otis
I.Q. conversions were not used, and this table applies only to total raw
scores. The coefficient of correlation between the Otis test and the Board
test (.7931) means considerable uncertainty in predicting one score from
another. The probable error of estimating a scholastic aptitude test score
from an Otis score is about 40. A "Predicted" S.A.T. score from an Otis score
of 50, for example, would be 420±40. This means that the chances are even that
the true S.A.T. score is between 380 and 460. The chances are also even that
the score is greater than 460 or less than 380, but become increasingly
smaller as the distance from these numbers becomes larger.
Otis Raw Score |
Otis IQ |
SAT score |
SAT %ile |
|
Otis Raw Score |
Otis IQ |
SAT score |
SAT %ile |
|
Otis Raw Score |
Otis IQ |
SAT score |
SAT %ile |
75 |
144 |
647 |
92 |
|
58 |
116 |
492 |
46 |
|
41 |
99 |
338 |
5 |
74 |
140 |
638 |
91 |
|
57 |
115 |
483 |
43 |
|
40 |
98 |
329 |
4 |
73 |
137 |
628 |
90 |
|
56 |
114 |
474 |
39 |
|
39 |
97 |
320 |
3 |
72 |
135 |
619 |
88 |
|
55 |
113 |
465 |
36 |
|
38 |
96 |
311 |
2 |
71 |
133 |
610 |
86 |
|
54 |
112 |
456 |
32 |
|
37 |
95 |
302 |
2 |
70 |
131 |
601 |
84 |
|
53 |
111 |
447 |
29 |
|
36 |
94 |
293 |
1 |
69 |
129 |
592 |
82 |
|
52 |
110 |
438 |
26 |
|
35 |
93 |
284 |
1 |
68 |
127 |
583 |
79 |
|
51 |
109 |
429 |
24 |
|
34 |
92 |
275 |
1 |
67 |
125 |
574 |
77 |
|
50 |
108 |
420 |
21 |
|
33 |
91 |
266 |
0.9 |
66 |
124 |
565 |
74 |
|
49 |
107 |
411 |
18 |
|
32 |
90 |
257 |
0.7 |
65 |
123 |
556 |
71 |
|
48 |
106 |
402 |
16 |
|
31 |
89 |
248 |
0.5 |
64 |
122 |
547 |
68 |
|
47 |
105 |
393 |
14 |
|
30 |
88 |
239 |
0.4 |
63 |
121 |
538 |
64 |
|
46 |
104 |
384 |
12 |
|
29 |
87 |
230 |
0.3 |
62 |
120 |
529 |
61 |
|
45 |
103 |
375 |
10 |
|
28 |
86 |
220 |
0.2 |
61 |
119 |
520 |
58 |
|
44 |
102 |
366 |
8 |
|
27 |
85 |
211 |
0.1 |
60 |
118 |
511 |
54 |
|
43 |
101 |
356 |
7 |
|
26 |
84 |
202 |
0.1 |
59 |
117 |
502 |
50 |
|
42 |
100 |
347 |
3 |
|
25 |
83 |
193 |
0.1 |
This table is of mainly historical interest because SAT scores have changed quite a bit since 1932. One lesson that can be drawn is about the uncertainty in converting scores between tests: the results are not very precise. Please keep this in mind when you are looking at my
GRE and SAT (unofficial) estimation pages.
Please send comments by e-mail to the author, Rodrigo de la Jara at .
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