Statistics of birth year

© Paul Cooijmans

Known birth years of test candidates as of 25 September 2019

Contents type: Personal information.   

1913 *
1920 *
1921 *
1924 *
1925 *
1926 *
1927 *
1928 *
1929 **
1933 ****
1935 ***
1937 ******
1938 *
1940 **
1941 ****
1942 *****
1943 ****
1944 ****
1945 ********
1946 *****
1947 **********
1948 *********
1949 *************
1950 **********
1951 **********
1952 *****************
1953 *************
1954 *************
1955 ******************
1956 ************************
1957 ***************************
1958 ***************************
1959 **********************
1960 *************************************
1961 ***************************
1962 ***************
1963 ********************************
1964 ***********************************
1965 **********************************
1966 ****************************
1967 ************************************
1968 ***********************************
1969 ******************************************
1970 *********************************************
1971 *************************************
1972 ***************************************
1973 *******************************************
1974 ****************************************************
1975 ******************************************
1976 **********************************************
1977 ********************************************
1978 **************************************************
1979 ***********************************************************
1980 ********************************************************
1981 ******************************************************************************
1982 ************************************************************
1983 ************************************************************
1984 *************************************************************************
1985 *********************************************************
1986 *************************************************
1987 **********************************************
1988 ************************************
1989 *******************************
1990 *****************************
1991 ********************
1992 *********************
1993 ******************
1994 **************
1995 ******************
1996 ******************
1997 **********
1998 *************
1999 **************
2000 ******
2001 ******
2002 ***
2003 **
2004 *

Remark: The slightly earlier median birth year of females may reflect the fact that women live longer than men on average.

Birth years of males

n = 1480

1913 *
1920 *
1921 *
1924 *
1925 *
1926 *
1929 *
1933 ****
1935 ***
1937 ***
1938 *
1940 **
1941 ***
1942 *****
1943 ***
1944 ****
1945 ******
1946 ***
1947 *******
1948 ********
1949 ************
1950 *******
1951 *******
1952 ***************
1953 **********
1954 *********
1955 ****************
1956 **********************
1957 *********************
1958 ********************
1959 ********************
1960 *******************************
1961 *********************
1962 ***********
1963 *********************
1964 ******************************
1965 *****************************
1966 ************************
1967 **********************************
1968 *****************************
1969 *********************************
1970 ***************************************
1971 *******************************
1972 ******************************
1973 ************************************
1974 *********************************************
1975 *************************************
1976 ************************************
1977 ***************************************
1978 *******************************************
1979 **********************************************
1980 *****************************************
1981 ****************************************************************
1982 **************************************************
1983 ************************************************
1984 *************************************************************
1985 ************************************************
1986 ******************************************
1987 **************************************
1988 ******************************
1989 ***************************
1990 *********************
1991 *****************
1992 *****************
1993 *****************
1994 **************
1995 ***************
1996 ***************
1997 **********
1998 ***********
1999 **************
2000 *****
2001 ******
2002 ***
2003 **
2004 *

Birth years of females

n = 297

1927 *
1928 *
1929 *
1937 ***
1941 *
1943 *
1945 **
1946 **
1947 ***
1948 *
1949 *
1950 **
1951 ***
1952 **
1953 ***
1954 ****
1955 **
1956 **
1957 ******
1958 ******
1959 **
1960 *****
1961 ******
1962 ****
1963 **********
1964 *****
1965 *****
1966 ****
1967 **
1968 ******
1969 ********
1970 *****
1971 ******
1972 *********
1973 *******
1974 *******
1975 *****
1976 **********
1977 *****
1978 *******
1979 *************
1980 ***************
1981 **************
1982 **********
1983 ************
1984 ************
1985 *********
1986 *******
1987 ********
1988 ******
1989 ****
1990 *******
1991 ***
1992 ****
1993 *
1995 *
1996 ***
1998 **
2000 *

Correlation of Year of birth with other tests by Paul Cooijmans

(Test index) Test name n r
(97) A-19 - Early experimental association test in Netherlandic, 23 items50.71
(88) Giga Test50.56
(47) Psychometrically Activated Grids Acerbate Neuroticism90.51
(50) Qoymans Automatic Test #2160.49
(72) Qoymans Automatic Test #1170.41
(105) Space, Time, and Hyperspace - Revision 2016310.39
(112) Combined Numerical and Spatial sections of Test For Genius - Revision 2016290.35
(109) The Bonsai Test - Revision 2016250.33
(73) Qoymans Automatic Test #3100.31
(111) Test For Genius - Revision 2016210.30
(110) Cooijmans Intelligence Test 5210.30
(84) Bonsai Test250.27
(71) Numerical Insight Test140.23
(57) Space, Time, and Hyperspace1730.22
(117) The Hammer Of Test-Hungry - Revision 2013160.22
(62) Reason Behind Multiple-Choice310.21
(7) The Final Test1190.18
(87) Cooijmans Intelligence Test - Form 2660.17
(11) Isis Test680.17
(82) Reason380.17
(104) The Final Test - Revision 2013170.15
(68) Numbers1080.12
(16) Lieshout International Mesospheric Intelligence Test910.10
(27) Spatial section of Test For Genius - Revision 20041290.10
(66) Test For Genius - Revision 2004800.07
(24) Reason - Revision 2008810.07
(107) The Alchemist Test170.07
(37) Problems In Gentle Slopes of the third degree220.07
(44) Associative LIMIT610.06
(116) Gliaweb Riddled Intelligence Test (old version)460.06
(77) Analogies #1290.06
(60) Association and Analogies (French)120.05
(36) Reflections In Peroxide190.04
(90) Analogies subtest of Long Test For Genius (French)110.04
(63) Long Test For Genius810.03
(56) Short Test For Genius610.01
(64) Long Test For Genius (French)10-0.00
(86) Evens23-0.01
(103) Problems In Gentle Slopes of the second degree23-0.01
(1) Cartoons of Shock54-0.02
(25) The Sargasso Test46-0.02
(108) Verbal section of Test For Genius - Revision 201622-0.03
(39) Combined Numerical and Spatial sections of Test For Genius - Revision 201057-0.03
(6) De Laatste Test7-0.03
(35) Intelligence Quantifier by assessment129-0.03
(28) The Test To End All Tests63-0.05
(40) Reason Behind Multiple-Choice - Revision 200879-0.05
(69) Odds26-0.06
(79) Association subtest of Long Test For Genius102-0.07
(48) Narcissus' last stand17-0.07
(83) KIT Intelligence Test - first attempts14-0.09
(2) Cooijmans Intelligence Test - Form 3143-0.09
(12) Cooijmans On-Line Test - Two-barrelled version32-0.10
(29) Words23-0.10
(15) Letters22-0.10
(19) Numerical section of Test For Genius - Revision 201084-0.11
(91) Association subtest of Long Test For Genius (French)11-0.11
(21) Psychometric Qrosswords19-0.11
(75) Analogies of Long Test For Genius93-0.11
(41) The LAW - Letters And Words19-0.11
(52) Qoymans Multiple-Choice #241-0.12
(85) Cooijmans Intelligence Test - Form 159-0.14
(4) A Paranoiac's Torture: Intelligence Test Utilizing Diabolic Exactitude25-0.14
(55) Spatial Insight Test26-0.16
(26) Verbal section of Test For Genius - Revision 2004114-0.16
(80) Qoymans Multiple-Choice #4159-0.16
(10) Genius Association Test103-0.17
(43) Test For Genius - Revision 201038-0.18
(106) Cooijmans Intelligence Test - Form 465-0.18
(23) Gliaweb Riddled Intelligence Test - Revision 2011154-0.18
(46) Labyrinthine LIMIT12-0.18
(74) Cooijmans On-Line Test28-0.20
(18) The Nemesis Test48-0.20
(45) Numerical and spatial sections of The Marathon Test42-0.21
(3) Qoymans Multiple-Choice #581-0.21
(59) Association and Analogies (German)6-0.22
(32) Spatial section of The Marathon Test43-0.23
(31) Numerical section of The Marathon Test44-0.23
(76) Analogies subtest of Long Test For Genius (Netherlandic)17-0.24
(5) Daedalus Test29-0.24
(30) Verbal section of The Marathon Test30-0.24
(14) Low Countries Aptitude Test7-0.26
(33) Problems In Gentle Slopes of the first degree19-0.27
(42) The Marathon Test28-0.27
(51) Qoymans Multiple-Choice #1138-0.29
(65) Long Test For Genius (Netherlandic)16-0.30
(53) Qoymans Multiple-Choice #3230-0.33
(0) Test of the Beheaded Man39-0.38
(70) A-22 - Early experimental association test in Netherlandic, 27 items (maximum score 31)11-0.39
(54) Test of Shock and Awe23-0.39
(81) Association subtest of Long Test For Genius (Netherlandic)20-0.40
(93) A-12 - Early experimental oral association test in Netherlandic, 40 items15-0.48
(67) A-18 - Early experimental association test in Netherlandic7-0.64
(8) Female Intelligence Test9-0.80

Weighted average of correlations: -0.051 (weighted sum: -228.81)

Conservatively estimated minimum g loading: -0.23

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 5 score pairs. All known pairs are used, including possible floor/ceiling scores or outliers.

Remark: The negative g loading means that earlier birth years do slightly better on the whole.

Correlation of Year of birth with tests by others

(Test index) Test name n r
(207) Chimera Test60.86
(203) Wechsler Adult Intelligence Scales for Children120.67
(245) Stanford-Binet140.62
(233) Hoeflin Power Test200.41
(232) GMAT110.40
(204) Chimera High Ability Riddle Test180.35
(225) Logima Strictica 36920.32
(229) Mega Test550.30
(211) Culture Fair Numerical Spatial Examination - Final version970.26
(230) Omega Contemplative Items Pool170.21
(220) Cattell Culture Fair730.16
(200) American College Testing program270.15
(226) Logima Strictica 24200.11
(234) Strict Logic Sequences Exam I1050.10
(219) Graduate Record Examination470.06
(236) International High IQ Society Miscellaneous tests780.05
(238) 916 Test310.04
(240) Strict Logic Spatial Exam 48430.02
(241) Ultra Test210.01
(223) Strict Logic Sequences Exam II23-0.02
(246) Sequentia Numerica Form I17-0.02
(244) Scholastic Aptitude Test (new)20-0.03
(239) Titan Test45-0.06
(213) Encephalist - R16-0.08
(242) Unknown and miscellaneous tests320-0.09
(243) Scholastic Aptitude Test (old)43-0.09
(217) G-test14-0.09
(206) W-8730-0.11
(212) Raven's Advanced Progressive Matrices (raw)41-0.12
(237) Sigma Test51-0.12
(247) Advanced Intelligence Test14-0.12
(224) T.R.I.14-0.15
(201) Wechsler Adult Intelligence Scales58-0.20
(218) Raven's Advanced Progressive Matrices (I.Q.)58-0.22
(205) Cito-toets22-0.23
(215) FITR-35-0.23
(231) Mysterium Entrance Exam46-0.28
(214) Epiq Tests15-0.30
(228) Miller Analogies Test (raw; old version)16-0.31
(227) Concep-T11-0.33
(202) Cattell Verbal12-0.35
(235) Nonverbal Cognitive Performance Examination57-0.35
(210) Drenth analogies5-0.47
(221) National I.Q. Tests9-0.55
(209) Drenth number series12-0.56
(208) California Test of Mental Maturity12-0.62

Weighted average of correlations: -0.003 (weighted sum: -5.58)

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 5 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.

Correlation of Year of birth with other tests by Paul Cooijmans - for females

(Test index) Test name n r
(56) Short Test For Genius40.77
(18) The Nemesis Test40.71
(68) Numbers60.65
(106) Cooijmans Intelligence Test - Form 440.58
(35) Intelligence Quantifier by assessment210.54
(7) The Final Test90.54
(16) Lieshout International Mesospheric Intelligence Test40.52
(1) Cartoons of Shock50.50
(63) Long Test For Genius70.46
(79) Association subtest of Long Test For Genius70.37
(24) Reason - Revision 200850.31
(57) Space, Time, and Hyperspace140.27
(23) Gliaweb Riddled Intelligence Test - Revision 2011120.19
(75) Analogies of Long Test For Genius80.16
(44) Associative LIMIT40.11
(87) Cooijmans Intelligence Test - Form 250.07
(40) Reason Behind Multiple-Choice - Revision 200850.03
(52) Qoymans Multiple-Choice #240.03
(26) Verbal section of Test For Genius - Revision 20044-0.03
(80) Qoymans Multiple-Choice #420-0.08
(2) Cooijmans Intelligence Test - Form 314-0.14
(81) Association subtest of Long Test For Genius (Netherlandic)6-0.28
(51) Qoymans Multiple-Choice #135-0.34
(3) Qoymans Multiple-Choice #55-0.34
(53) Qoymans Multiple-Choice #352-0.48
(76) Analogies subtest of Long Test For Genius (Netherlandic)4-0.62
(8) Female Intelligence Test4-0.71
(116) Gliaweb Riddled Intelligence Test (old version)4-0.73
(10) Genius Association Test6-0.76
(93) A-12 - Early experimental oral association test in Netherlandic, 40 items4-0.78
(67) A-18 - Early experimental association test in Netherlandic4-0.95

Weighted average of correlations: -0.051 (weighted sum: -14.84)

Conservatively estimated minimum g loading among females: -0.23

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.

Estimated loadings of Year of birth 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.

Typeg loading of Year of birth on that type
Verbal-0.40
Numerical-0.12
Spatial0.35
Logical-0.05
Heterogeneous-0.20

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

Balanced g loading = -0.09

Remark: It seems that persons with earlier birth years do better on verbal tests and persons with later birth years do better on spatial tests. This matches the existing notion in psychometrics that spatial ability peaks early, and recalls the phenomenon that literary authors tend to reach their peaks beyond middle age, like in their sixties.

National medians for Year of birth

Country n median
China191992.0
Malaysia31992.0
Korea_South211988.0
Argentina81985.0
Czech_Republic31985.0
Thailand31984.0
Bulgaria81983.0
Cuba21983.0
Serbia21983.0
Romania61982.5
Austria131982.0
Mexico91982.0
Slovakia21982.0
New_Zealand61981.5
Hungary31981.0
Japan161981.0
India301980.5
Chile31980.0
Greece271980.0
Italy251980.0
Poland181979.5
Singapore61979.0
Slovenia61978.0
Bosnia_and_Herzegovina51977.0
Iran31977.0
Israel81977.0
Portugal81977.0
Spain321977.0
Yugoslavia71977.0
Germany821976.5
Brazil191976.0
Croatia51976.0
Sweden801975.5
Cyprus31975.0
Philippines51975.0
Switzerland61975.0
Turkey111975.0
United_Kingdom561975.0
United_States4081975.0
Canada431974.0
Finland501974.0
Norway171974.0
Netherlands1531973.0
Australia261972.0
Belgium361970.0
Denmark191970.0
Malta21970.0
Russia41969.5
France341969.0
Luxembourg21969.0
South_Africa91968.0
Hong_Kong51965.0

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

Correlation with national I.Q.'s of Year of birth

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

Correlation of Year of birth with personal details

Personalia n r
P.S.I.A. Aspergoid3590.34
P.S.I.A. Rare3590.28
P.S.I.A. Deviance factor4660.27
P.S.I.A. Cruel3590.25
P.S.I.A. Antisocial3590.23
Mother's educational level9210.23
P.S.I.A. Introverted3590.23
P.S.I.A. Cold3590.22
P.S.I.A. Neurotic3590.21
P.S.I.A. Just3590.20
Gifted Adult's Inventory of Aspergerisms1630.20
P.S.I.A. System factor2220.16
Father's educational level9130.14
P.S.I.A. Rational3590.08
P.S.I.A. Extreme3590.08
Sex17780.04
Disorders (own)9830.03
Cooijmans Inventory of Neo-Marxist Attitudes1260.02
Disorders (parents and siblings)960-0.03
P.S.I.A. True359-0.09
P.S.I.A. Orderly359-0.16
P.S.I.A. Ethics factor466-0.20
Observed associative horizon62-0.26
Observed behaviour140-0.28
Educational level979-0.47

Remark: Earlier birth years have higher educational levels, behave better, have wider associative horizons, and are more ethical and orderly. Later birth years score higher on various indicators of deviance, introversion, and antisocial behaviour, and have better educated parents. These tendencies are more pronounced in males than in females.

Correlation with personal details of Year of birth - within females

Personalia n r
Gifted Adult's Inventory of Aspergerisms290.32
P.S.I.A. Antisocial620.24
Mother's educational level1230.22
Father's educational level1240.20
Observed behaviour190.17
P.S.I.A. Orderly620.13
P.S.I.A. Just620.12
P.S.I.A. Cruel620.07
P.S.I.A. Rational620.07
P.S.I.A. Extreme620.07
P.S.I.A. Deviance factor830.01
P.S.I.A. Rare62-0.00
Disorders (own)136-0.02
P.S.I.A. System factor38-0.03
P.S.I.A. Aspergoid62-0.05
Observed associative horizon9-0.06
Disorders (parents and siblings)133-0.07
P.S.I.A. Neurotic62-0.11
P.S.I.A. Introverted62-0.14
P.S.I.A. Cold62-0.16
Cooijmans Inventory of Neo-Marxist Attitudes12-0.17
P.S.I.A. Ethics factor83-0.28
P.S.I.A. True62-0.29
Educational level137-0.31

Correlation with personal details of Year of birth - within males

Personalia n r
P.S.I.A. Aspergoid2970.40
P.S.I.A. Rare2970.34
P.S.I.A. Deviance factor3830.32
P.S.I.A. Introverted2970.29
P.S.I.A. Cold2970.29
P.S.I.A. Cruel2970.27
P.S.I.A. Neurotic2970.26
Gifted Adult's Inventory of Aspergerisms1320.25
P.S.I.A. Antisocial2970.23
Mother's educational level7970.23
P.S.I.A. Just2970.22
P.S.I.A. System factor1840.18
Father's educational level7880.14
P.S.I.A. Rational2970.09
P.S.I.A. Extreme2970.08
Cooijmans Inventory of Neo-Marxist Attitudes1130.08
Disorders (own)8440.04
Disorders (parents and siblings)826-0.03
P.S.I.A. True297-0.05
P.S.I.A. Ethics factor383-0.19
P.S.I.A. Orderly297-0.20
Observed behaviour121-0.27
Observed associative horizon53-0.30
Educational level841-0.50

Estimated g factor loadings upward and downward of particular scores

In parentheses the number of score pairs on which that estimated g factor loading is based. The goal of this is to verify the hypothesis that g becomes less important, accounts for a smaller proportion of the variance, at higher I.Q. levels. The mere fact of restricting the range like this also depresses the g loading compared to computing it over the test's full range, so it would be normal for both values to be lower than the test's full-range g loading.

Raw scoreUpward g (n)Downward g (n)
1913-0.23 (4490)NaN (0)
1957-0.35 (4043)0.41 (464)
1966.5-0.37 (3211)0.41 (1243)
1976-0.36 (2245)0.30 (2335)
1985.5-0.40 (914)0.15 (3514)
1995-0.29 (239)-0.19 (4267)
2004NaN (0)-0.23 (4490)

Remark: Although these are all small, it can be deduced from this table that the g loading of birth year is negative for the recent birth years and positive for the remote birth years. In other words, that the middle generations score highest. This is consistent with the known scores by age.