# Is g-factor affected by the Flynn effect

**URL:** <https://boards.straightdope.com/t/is-g-factor-affected-by-the-flynn-effect/1008999>\
**Category:** Factual Questions\
**Created:** [October 20, 2024, 4:46pm UTC](https://boards.straightdope.com/t/is-g-factor-affected-by-the-flynn-effect/1008999 "2024-10-20T16:46:07Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![Wesley\_Clark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/wesley_clark/32/20581_2.png) [@Wesley\_Clark](https://boards.straightdope.com/u/Wesley_Clark)\
**Post date:** [October 20, 2024, 4:46pm UTC](https://boards.straightdope.com/t/is-g-factor-affected-by-the-flynn-effect/1008999/1 "2024-10-20T16:46:07Z")

</div>

> **[Flynn effect](https://en.wikipedia.org/wiki/Flynn_effect)**
>
> The Flynn effect is the substantial and long-sustained increase in both fluid and crystallized intelligence test scores that were measured in many parts of the world over the 20th century, named after researcher James Flynn (1934–2020). When intelligence quotient (IQ) tests are initially standardized using a sample of test-takers, by convention the average of the test results is set to 100 and their standard deviation is set to 15 or 16 IQ points. When IQ tests are revised, they are again s Tes...

> The **Flynn effect** is the substantial and long-sustained increase in both [fluid and crystallized intelligence](https://en.wikipedia.org/wiki/Fluid_and_crystallized_intelligence) test scores that were measured in many parts of the world over the 20th century, named after researcher [James Flynn](https://en.wikipedia.org/wiki/James_Flynn_(academic)) (1934–2020).[[1]](https://en.wikipedia.org/wiki/Flynn_effect#cite_note-1)[[2]](https://en.wikipedia.org/wiki/Flynn_effect#cite_note-baker-2) When [intelligence quotient](https://en.wikipedia.org/wiki/Intelligence_quotient) (IQ) tests are initially [standardized](https://en.wikipedia.org/wiki/Standard_score#Standardizing_in_mathematical_statistics) using a [sample](https://en.wikipedia.org/wiki/Sample_(statistics)) of test-takers, by convention the average of the test results is set to 100 and their [standard deviation](https://en.wikipedia.org/wiki/Standard_deviation) is set to 15 or 16 IQ points. When IQ tests are revised, they are again standardized using a new sample of test-takers, usually born more recently than the first; the average result is set to 100. When the new test subjects take the older tests, in almost every case their average scores are significantly above 100.

[![](https://upload.wikimedia.org/wikipedia/commons/thumb/4/41/Ourworldindata_wisc-iq-gains-over-time-flynn-2007.png/1024px-Ourworldindata_wisc-iq-gains-over-time-flynn-2007.png) ](https://upload.wikimedia.org/wikipedia/commons/thumb/4/41/Ourworldindata_wisc-iq-gains-over-time-flynn-2007.png/1024px-Ourworldindata_wisc-iq-gains-over-time-flynn-2007.png)

So IQ has gone up in the 20th century (my understanding is the Flynn effect stopped and started to reverse around 20 years ago though).

however g-factor is a broader measure of cognitive abilities than intelligence.

> **[g factor (psychometrics)](https://en.wikipedia.org/wiki/G_factor_(psychometrics))**
>
> The g factor\[a\] is a construct developed in psychometric investigations of cognitive abilities and human intelligence. It is a variable that summarizes positive correlations among different cognitive tasks, reflecting the fact that an individual's performance on one type of cognitive task tends to be comparable to that person's performance on other kinds of cognitive tasks.\[citation needed\] The g factor typically accounts for 40 to 50 percent of the between-individual performance differences on ...

Does anyone know if g-factor grew in the 20th century the way IQ grew, or did g-factor stay the same?