Statistics of Disorders in parents or siblings

Introduction

For many years, candidates have been asked to report whether any psychiatric disorders occur among their parents or siblings. Below are the available statistics of that field, when "yes" is coded as 1 and "no" is coded as 0.

Scores on Disorders (parents and siblings) as of 10 February 2021

Contents type: Personal information.   

• n: 1024
• Mean: 0.24
• Standard deviation: 0.43
• Range: 1.0
• Maximum possible: 1
• Male mean: 0.23 (n = 885)
• Female mean: 0.28 (n = 138)
• Intersexual mean: 0.00 (n = 1)

Note: Since the values are either 0 or 1, the above means can be understood as proportions, so that for instance 0.24 means that 24 percent has answered "yes".

Correlation of Disorders (parents and siblings) with other tests by I.Q. Tests for the High Range

Weighted average of correlations: -0.133 (N = 3671, weighted sum = -487.95)

Conservatively estimated minimum g loading: -0.36

Remark: Just like disorders in the candidates themselves, disorders in parents or siblings correlate negatively with I.Q. and g.

Correlation of Disorders (parents and siblings) with tests by others

Weighted average of correlations: -0.138 (N = 991, weighted sum = -136.35)

Remark: Tests by others reveal a similar negative correlation.

Correlation of Disorders (parents and siblings) with other tests by I.Q. Tests for the High Range - for females

Weighted average of correlations: -0.226 (N = 113, weighted sum = -25.59)

Conservatively estimated minimum g loading among females: -0.48

Remark: As often, the g loading (and correlation) in females is higher (negative in this case) than the overall one. Since this is seen in I.Q. test statistical reports too, it may just be that high-range tests measure g better in females than in males, and may have nothing to do with the correlation between disorders and g as such.

Estimated loadings of Disorders (parents and siblings) 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.

N = 2970

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

Balanced g loading = -0.36

National means for Disorders (parents and siblings)

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 Disorders (parents and siblings)

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

• r = 0.01 (n = 1019)

Correlation of Disorders (parents and siblings) with personal details

Observation: The highest correlation is with disorders in the candidates themselves.

[More statistical reports]