Statistics of birth year

© Feb. 2011 Paul Cooijmans

Known birth years of test candidates

Contents type: Personal information.   

1913 *
1920 *
1921 *
1924 *
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 *

Males' birth years

n = 1063

1913 *
1920 *
1921 *
1924 *
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 *

Females' birth years

n = 252

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 **

Correlation of Year of birth with tests by Paul Cooijmans

Test n r
Cooijmans On-Line Test (Two-barrelled)50.90
A-19 - Early experimental association test in Netherlandic, 23 items50.71
Giga Test50.56
Qoymans Automatic Test #2160.48
Numerical and spatial sections of The Marathon Test130.44
Spatial section of The Marathon Test130.44
Qoymans Automatic Test #1170.41
Bonsai Test250.39
The Marathon Test130.38
Lieshout International Mesospheric Intelligence Test510.35
Reason380.34
Qoymans Automatic Test #3100.31
Isis Test400.30
Numerical section of The Marathon Test140.28
Female Intelligence Test80.26
Verbal section of The Marathon Test130.26
Space, Time, and Hyperspace1730.25
Words120.23
Numerical Insight Test140.23
Reason Behind Multiple-Choice310.21
The Final Test1140.19
Spatial section of Test For Genius - Revision 2004810.19
Cooijmans Intelligence Test - Form 2660.17
Reason - Revision 2008250.17
Long Test For Genius (Netherlandic)160.17
Analogies subtest of Long Test For Genius (Netherlandic)170.17
Numbers1080.15
Associative LIMIT Test290.12
Gliaweb Riddled Intelligence Test380.10
Test For Genius - Revision 2004780.08
Reason Behind Multiple-Choice - Revision 2008250.07
Cartoons of Shock250.06
Analogies #1280.06
The Sargasso Test200.06
Association and Analogies (French)120.05
Intelligence Quantifier by assessment930.05
Analogies subtest of Long Test For Genius (French)110.04
Long Test For Genius810.03
The LAW - Letters And Words80.02
The Test To End All Tests500.02
Short Test For Genius610.01
Long Test For Genius (French)10-0.00
De Laatste Test7-0.01
KIT Intelligence Test - first attempts14-0.03
Test of the Beheaded Man14-0.03
Letters11-0.03
Cooijmans Intelligence Test - Form 332-0.04
Association subtest of Long Test For Genius101-0.06
Evens23-0.08
Association subtest of Long Test For Genius (French)11-0.11
The Nemesis Test22-0.11
Analogies of Long Test For Genius93-0.11
Odds25-0.11
Qoymans Multiple-Choice #525-0.12
Qoymans Multiple-Choice #241-0.12
Verbal section of Test For Genius - Revision 200480-0.13
Cooijmans Intelligence Test - Form 159-0.14
Spatial Insight Test26-0.16
Association subtest of Long Test For Genius (Netherlandic)20-0.16
Qoymans Multiple-Choice #4158-0.16
Daedalus Test13-0.22
Association and Analogies (German)6-0.22
A Paranoiac's Torture: Intelligence Test Utilizing Diabolic Exactitude6-0.24
Low Countries Aptitude Test7-0.26
Qoymans Multiple-Choice #1138-0.29
Genius Association Test70-0.30
Cooijmans On-Line Test26-0.32
Qoymans Multiple-Choice #3229-0.33
A-22 - Early experimental association test in Netherlandic, 27 items (maximum score 31)11-0.38
Test of Shock and Awe22-0.46
Problems In Gentle Slopes of the first degree5-0.47
A-12 - Early experimental oral association test in Netherlandic, 40 items15-0.48
Psychometric Qrosswords11-0.56
A-18 - Early experimental association test in Netherlandic7-0.64

Weighted average of correlations: -0.003

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 to obtain the true, honest statistics; correlations have not been artificially inflated by leaving out ceiling scores, outliers or other anomalies.

Correlation of Year of birth with tests by others

Test n r
Chimera Test60.86
Wechsler Adult Intelligence Scales for Children90.81
GMAT90.80
Stanford-Binet150.49
Hoeflin Power Test200.41
Chimera High Ability Riddle Test180.35
Logima Strictica 36820.31
Culture Fair Numerical Spatial Examination - Final version900.26
Mega Test550.26
Omega Contemplative Items Pool170.21
Strict Logic Sequences Exam I940.10
American College Testing program260.04
916 Test300.04
Strict Logic Spatial Exam 48370.02
Logima Strictica 60130.02
Strict Logic Sequences Exam II180.01
Graduate Record Examination370.00
Cattell Culture Fair650.00
Scholastic Aptitude Test (old)35-0.01
Titan Test44-0.04
Ultra Test19-0.07
Encephalist - R16-0.08
Unknown tests110-0.09
Raven's Advanced Progressive Matrices (raw)34-0.09
G-test12-0.11
W-8728-0.11
Sigma Test51-0.12
Scholastic Aptitude Test (new)17-0.17
International High IQ Society Miscellaneous tests40-0.18
Raven's Advanced Progressive Matrices (I.Q.)53-0.18
T.R.I.13-0.20
Cito-toets22-0.23
Wechsler Adult Intelligence Scales49-0.23
FITR-35-0.23
Mysterium Entrance Exam44-0.28
Epiq Tests15-0.30
Concep-T11-0.33
Miller Analogies Test (raw; old version)14-0.34
Cattell Verbal12-0.35
Nonverbal Cognitive Performance Examination57-0.35
Drenth number series9-0.50
National I.Q. Tests9-0.55
California Test of Mental Maturity11-0.66

Weighted average of correlations: -0.009

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 to obtain the true, honest statistics; correlations have not been artificially inflated by leaving out ceiling scores, outliers or other anomalies.

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 tests by Paul Cooijmans - for females

Test n r
Short Test For Genius40.77
Numbers60.65
The Final Test80.61
Intelligence Quantifier by assessment180.50
Long Test For Genius70.46
Association subtest of Long Test For Genius70.37
Space, Time, and Hyperspace140.27
Analogies of Long Test For Genius80.16
Cooijmans Intelligence Test - Form 250.07
Qoymans Multiple-Choice #240.03
Qoymans Multiple-Choice #420-0.08
Association subtest of Long Test For Genius (Netherlandic)6-0.28
Qoymans Multiple-Choice #135-0.34
Qoymans Multiple-Choice #351-0.47
Analogies subtest of Long Test For Genius (Netherlandic)4-0.62
Gliaweb Riddled Intelligence Test4-0.73
A-12 - Early experimental oral association test in Netherlandic, 40 items4-0.78
A-18 - Early experimental association test in Netherlandic4-0.95

Weighted average of correlations: -0.094

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 to obtain the true, honest statistics; correlations have not been artificially inflated by leaving out ceiling scores, outliers or other anomalies.

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-0.38
Numerical0.31
Spatial0.48
Logical0.25
Heterogeneous0.28

There is no overlap between the categories in this table as a result of leaving out compound tests.

Balanced g loading = 0.19

Remark: Although these are all very small, it does appear that on verbal items candidates with earlier birth years do slightly better, while for all other item types it is opposite.

National means for Year of birth

Country n mean score
Malaysia21984.00
China81983.88
Argentina61983.50
Bulgaria51983.00
Cyprus21983.00
Austria101982.10
Israel61980.83
Poland111980.09
Korea_South71980.00
India231979.91
Yugoslavia71978.00
Switzerland31977.33
Chile21977.00
Greece161976.56
Bosnia_and_Herzegovina41976.50
Croatia41976.25
Japan91975.89
Czech_Republic31975.67
Mexico81975.63
Hungary21975.50
Brazil171974.00
Singapore51973.80
Italy141972.93
Spain221972.82
Iran31972.67
Sweden521972.56
United_Kingdom401972.55
Philippines41972.50
Norway131971.46
Netherlands1351971.22
Germany431971.09
Romania31970.67
Denmark101970.60
Finland381970.42
New_Zealand51970.20
Malta21970.00
Canada311969.16
Luxembourg21969.00
United_States2801968.71
Turkey91968.67
Belgium341968.53
Australia201968.05
France251967.84
Russia21966.50
South_Africa61966.17
Thailand21966.00
Slovenia31965.33
Portugal41963.75
Hong_Kong31963.33

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 of Year of birth with personal details

Personalia n r
P.S.I.A. Aspergoid - Revision 2007260.45
P.S.I.A. Antisocial - Revision 2007260.43
P.S.I.A. Rare - Revision 2007260.35
P.S.I.A. Cold - Revision 2007260.32
P.S.I.A. Cruel - Revision 2007260.25
P.S.I.A. Cruel2920.24
P.S.I.A. Aspergoid2920.24
P.S.I.A. Introverted - Revision 2007260.24
P.S.I.A. Antisocial2920.23
P.S.I.A. System factor - Revision 2007260.23
Mother's educational level5880.22
P.S.I.A. Deviance factor4010.20
P.S.I.A. Just - Revision 2007260.20
P.S.I.A. Neurotic2920.20
P.S.I.A. Deviance factor - Revision 2007260.19
P.S.I.A. Rare2920.19
Father's educational level5810.16
Gifted Adult's Inventory of Aspergerisms1230.16
P.S.I.A. Just2920.14
P.S.I.A. Introverted2920.12
P.S.I.A. Cold2920.09
P.S.I.A. Rational - Revision 2007260.07
P.S.I.A. Rational2920.05
P.S.I.A. Extreme2920.03
P.S.I.A. Extreme - Revision 2007260.03
Sex1315-0.01
Disorders (own)638-0.02
P.S.I.A. Neurotic - Revision 200726-0.06
Disorders (parents and siblings)619-0.06
P.S.I.A. System factor156-0.09
P.S.I.A. Orderly - Revision 200726-0.12
P.S.I.A. True292-0.15
Observed associative horizon44-0.15
Observed behaviour108-0.19
P.S.I.A. Orderly292-0.25
P.S.I.A. Ethics factor401-0.27
P.S.I.A. True - Revision 200726-0.30
P.S.I.A. Ethics factor - Revision 200726-0.33
Educational level627-0.51

Correlation with personal details of Year of birth - within females

Personalia n r
Gifted Adult's Inventory of Aspergerisms240.32
Mother's educational level880.26
P.S.I.A. Rational550.22
Observed behaviour170.19
Father's educational level890.17
P.S.I.A. Just550.15
P.S.I.A. Antisocial550.08
Observed associative horizon50.07
P.S.I.A. Extreme550.05
P.S.I.A. Cruel550.01
P.S.I.A. Deviance factor76-0.02
P.S.I.A. Orderly55-0.02
Disorders (parents and siblings)98-0.03
Disorders (own)103-0.03
P.S.I.A. System factor31-0.09
P.S.I.A. Neurotic55-0.11
P.S.I.A. Aspergoid55-0.13
P.S.I.A. Rare55-0.16
P.S.I.A. True55-0.18
P.S.I.A. Cold55-0.19
P.S.I.A. Introverted55-0.19
P.S.I.A. Ethics factor76-0.20
Educational level101-0.39

Correlation with personal details of Year of birth - within males

Personalia n r
P.S.I.A. Aspergoid - Revision 2007240.42
P.S.I.A. Antisocial - Revision 2007240.33
P.S.I.A. Aspergoid2370.32
P.S.I.A. Cold - Revision 2007240.30
P.S.I.A. Cruel2370.30
P.S.I.A. Rare - Revision 2007240.28
P.S.I.A. Introverted - Revision 2007240.27
P.S.I.A. Rare2370.27
P.S.I.A. Antisocial2370.26
P.S.I.A. Deviance factor3250.26
P.S.I.A. Cruel - Revision 2007240.25
P.S.I.A. Neurotic2370.24
Mother's educational level5000.21
P.S.I.A. Deviance factor - Revision 2007240.19
P.S.I.A. Introverted2370.19
P.S.I.A. System factor - Revision 2007240.17
Gifted Adult's Inventory of Aspergerisms990.17
P.S.I.A. Cold2370.16
Father's educational level4920.16
P.S.I.A. Just2370.15
P.S.I.A. Just - Revision 2007240.10
P.S.I.A. Rational2370.06
P.S.I.A. Extreme - Revision 2007240.05
P.S.I.A. Extreme2370.02
P.S.I.A. Rational - Revision 2007240.00
Disorders (own)535-0.02
P.S.I.A. Neurotic - Revision 200724-0.05
Disorders (parents and siblings)521-0.06
P.S.I.A. System factor125-0.09
P.S.I.A. Orderly - Revision 200724-0.11
P.S.I.A. True237-0.14
Observed associative horizon39-0.18
P.S.I.A. True - Revision 200724-0.20
Observed behaviour91-0.21
P.S.I.A. Ethics factor - Revision 200724-0.25
P.S.I.A. Orderly237-0.29
P.S.I.A. Ethics factor325-0.29
Educational level526-0.54

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:

Estimated g factor loadings Upward and Downward of specific scores

In parentheses the number of score pairs on which that estimated g factor loading is based. The Upward and Downward values are calculated including the pertinent score itself. It is normal that g factor loadings go down when the range is restricted, so some inevitable depression must be taken into account.

ScoreUpward (n)Downward (n)
1913-0.05 (2840)NaN (0)
1947-0.21 (2716)0.58 (93)
1956-0.33 (2484)0.38 (302)
1965-0.31 (1948)0.43 (858)
1974-0.33 (1206)0.34 (1600)
1983-0.51 (475)0.18 (2329)
1995NaN (0)-0.05 (2840)

Remark: Although these are all small, it can be deduced 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.