Statistics of Isis Test

© Paul Cooijmans

Scores on Isis Test as of 21 December 2020

Contents type: Verbal, numerical.   Period: 2001-present

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Note: Means instead of medians are used in this report because of the very limited variance in scores, which makes medians less informative.

Correlation of Isis Test with other tests by I.Q. Tests for the High Range

(Test index) Test name n r
(113) The Piper's Test60.87
(107) The Alchemist Test70.82
(46) Labyrinthine LIMIT50.82
(56) Short Test For Genius40.81
(114) Dicing with death70.73
(18) The Nemesis Test250.68
(106) Cooijmans Intelligence Test - Form 4120.66
(68) Numbers110.66
(116) Gliaweb Riddled Intelligence Test (old version)40.64
(47) Psychometrically Activated Grids Acerbate Neuroticism60.64
(21) Psychometric Qrosswords70.63
(30) Verbal section of The Marathon Test100.63
(42) The Marathon Test90.62
(82) Reason70.62
(12) Cooijmans On-Line Test - Two-barrelled version120.62
(69) Odds60.60
(35) Intelligence Quantifier by assessment240.57
(110) Cooijmans Intelligence Test 5130.57
(31) Numerical section of The Marathon Test110.57
(66) Test For Genius - Revision 2004160.55
(0) Test of the Beheaded Man140.54
(33) Problems In Gentle Slopes of the first degree80.54
(36) Reflections In Peroxide160.53
(62) Reason Behind Multiple-Choice70.53
(45) Numerical and spatial sections of The Marathon Test110.52
(104) The Final Test - Revision 2013100.51
(48) Narcissus' last stand140.50
(15) Letters80.50
(103) Problems In Gentle Slopes of the second degree130.50
(117) The Hammer Of Test-Hungry - Revision 201390.49
(109) The Bonsai Test - Revision 2016130.47
(10) Genius Association Test220.45
(41) The LAW - Letters And Words70.42
(37) Problems In Gentle Slopes of the third degree80.42
(32) Spatial section of The Marathon Test110.42
(4) A Paranoiac's Torture: Intelligence Test Utilizing Diabolic Exactitude200.40
(1) Cartoons of Shock140.40
(27) Spatial section of Test For Genius - Revision 2004240.37
(29) Words70.36
(23) Gliaweb Riddled Intelligence Test - Revision 2011140.35
(25) The Sargasso Test190.35
(108) Verbal section of Test For Genius - Revision 2016130.34
(44) Associative LIMIT180.34
(84) Bonsai Test80.34
(26) Verbal section of Test For Genius - Revision 2004240.32
(3) Qoymans Multiple-Choice #5320.32
(28) The Test To End All Tests200.32
(55) Spatial Insight Test40.26
(87) Cooijmans Intelligence Test - Form 290.25
(40) Reason Behind Multiple-Choice - Revision 2008320.24
(57) Space, Time, and Hyperspace110.24
(5) Daedalus Test110.23
(43) Test For Genius - Revision 2010110.22
(63) Long Test For Genius90.21
(7) The Final Test120.21
(16) Lieshout International Mesospheric Intelligence Test210.17
(111) Test For Genius - Revision 2016130.16
(39) Combined Numerical and Spatial sections of Test For Genius - Revision 2010130.15
(75) Analogies of Long Test For Genius90.14
(2) Cooijmans Intelligence Test - Form 3210.12
(24) Reason - Revision 2008320.08
(19) Numerical section of Test For Genius - Revision 2010240.06
(80) Qoymans Multiple-Choice #4150.06
(105) Space, Time, and Hyperspace - Revision 2016160.03
(112) Combined Numerical and Spatial sections of Test For Genius - Revision 201615-0.04
(79) Association subtest of Long Test For Genius9-0.17

Weighted average of correlations: 0.373 (N = 873, weighted sum = 325.30)

Conservatively estimated minimum g loading: 0.61

Ranking in above table is based on the unrounded correlations. All available data is present in this table, no tests are left out except for those with less than 4 score pairs. All known pairs are used, including possible floor/ceiling scores or outliers.

Note: The correlations with other tests are uncommonly low as a result of the limited variance of raw scores on this test.

Correlation of Isis Test with tests by others

(Test index) Test name n r
(239) Titan Test90.46
(201) Wechsler Adult Intelligence Scales80.37
(242) Unknown and miscellaneous tests280.24
(234) Strict Logic Sequences Exam I90.10
(225) Logima Strictica 3680.08
(243) Scholastic Aptitude Test (old)4-0.10
(240) Strict Logic Spatial Exam 486-0.26

Weighted average of correlations: 0.186 (N = 72, weighted sum = 13.40)

Ranking in above table is based on the unrounded correlations. All available data is present in this table, no tests are left out except for those with less than 4 score pairs. All known pairs are used, including possible floor/ceiling scores or outliers.

Please be aware that correlations with these external tests are in most cases affected (depressed, typically) by one or more of the following: (1) Little overlap with the object test because of the much lower ceilings and inherent ceiling effects of the tests used in regular psychology; (2) Candidates reporting scores selectively, for instance only the higher ones while withholding lower ones; (3) Candidates reporting, or having been reported by psychometricians, incorrect scores.

Estimated loadings of Isis Test on particular item types

These are estimated g factor loadings, but against homogeneous tests (containing only particular item types) as opposed to non-compound heterogeneous tests. Although tending to surprise the lay person, it is not uncommon for tests to have high loadings on item types they do not actually contain themselves. Such loadings reflect the empirical fact that most tests for mental abilities measure primarily g, regardless of their contents; that the major part of test score variance is caused by g, and only a minor part by factors germane to particular item types. It is of key importance to understand that this is a fact of nature, a natural phenomenon, and not something that was built into the tests by the test constructors.

Typeng loading of Isis Test on that type

N = 661

Compound tests have been left out of this table to avoid overlap.

Balanced g loading = 0.56

National means for Isis Test

Country n mean score

For reasons of privacy, only countries with 2 or more candidates are included in this table. Ranking is based on the unrounded means, and then alphabetic.

Correlation with national I.Q.'s of Isis Test

Correlation of this test with national average I.Q.'s published by Lynn and Vanhanen:

Correlation of Isis Test with personal details

Personalia n r
Observed associative horizon90.79
P.S.I.A. Rational - Revision 2007110.73
P.S.I.A. Just - Revision 2007110.56
P.S.I.A. Ethics factor - Revision 2007110.55
P.S.I.A. True - Revision 2007110.46
Observed behaviour230.46
P.S.I.A. System factor - Revision 2007110.45
P.S.I.A. Introverted - Revision 2007110.40
P.S.I.A. Cold - Revision 2007110.37
P.S.I.A. Deviance factor - Revision 2007110.20
P.S.I.A. Extreme - Revision 2007110.17
Year of birth790.14
P.S.I.A. Orderly - Revision 2007110.10
Gifted Adult's Inventory of Aspergerisms180.07
Mother's educational level650.03
P.S.I.A. Aspergoid - Revision 2007110.03
Father's educational level62-0.00
P.S.I.A. Rare - Revision 200711-0.03
P.S.I.A. Antisocial - Revision 200711-0.09
Educational level69-0.09
Disorders (own)68-0.14
Disorders (parents and siblings)68-0.17
P.S.I.A. Neurotic - Revision 200711-0.18
P.S.I.A. Cruel - Revision 200711-0.46
Cooijmans Inventory of Neo-Marxist Attitudes8-0.85

Reliability and error

Due to the small number of items and limited variance in scores and item scores, it is not possible to compute reliability and error meaningfully for this test from its internal statistics. What can be said is that a test's reliability is necessarily higher than its g loading because reliability forms the upper limit of a test's possible correlations with any other variables.

Scores by age

Age class n mean score
70 to 7410.0
60 to 6410.0
55 to 5930.0
50 to 5460.0
45 to 4950.2
40 to 4450.6
35 to 3990.0
30 to 3480.1
25 to 29160.1
22 to 24110.5
20 or 2140.0
18 or 1970.3

N = 79

Scores by year taken

Year taken n mean score

ryear taken × mean score = 0.16 (N = 81)

Robustness and overall test quality

Item analysis

Item statistics are not published as that would help future candidates. To detect bad items, answers and comments from candidates are studied, as well as, for each problem, the correlation with total score and the proportion of candidates getting it wrong (hardness of the item). Possible bad items are removed or revised, resulting in a revised version of the test.