A note about Mensa

The page about Mensa on German Wikipedia (https://de.wikipedia.org/wiki/Mensa_in_Deutschland) contains an interesting passage:

The criterion for membership in Mensa is an intelligence quotient that is higher than that of 98% of the population. In the intelligence tests commonly used in Germany (mean 100, standard deviation 15), this corresponds to a score of 130 or higher. Mensa offers its own intelligence test for this purpose, which is evaluated by a psychologist. This test is approved for persons aged fourteen and older. External assessments, e.g. from registered psychologists, can also be accepted; for children under the age of fourteen, this is the only option. Almost half of new members submit external assessments. High IQ scores are often first achieved in tests independent of Mensa, which then draws attention to the topic of giftedness and Mensa.

That means that almost half of the Mensa members have probably practiced dozens of intelligence tests until they once reached a score that qualified them for Mensa membership. Perhaps they even took the same tests several times.

In my opinion, this justifies the requirement of an IQ of 140 or higher for membership in Prudentia.

Claus D. Volko 

Comments

  1. Igor DAugust 29, 2025 at 7:27 AM

    The paragraph doesn't imply that half of Mensa members practiced dozens of tests. The external tests they talk about are official tests that are conducted by licensed psychologist outside Mensa test sessions. There is a pretty limited number of such official tests and each test session with a psychologist costs an un-negligible amount of money (hundreds of euros/dollars). It's very unlikely that somebody took more than one or two such tests. From personal experience, I can say that I took the WAIS (on a private testing session) and then applied to Mensa with its result. This is exactly what this paragraph says.

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  2. Kevin ChenSeptember 4, 2025 at 5:45 PM

    Hi, I found this blog from the ISPE Facebook. I believe I have a valuable perspective to offer as someone who has taken both the WAIS and the Mensa admission test. I took the Mensa test for another data point and to avoid the embarrassment associated with emailing the psychologist who tested me for a signature.
    The American Mensa admission criteria states
    "American Mensa accepts a score at or above the 98th percentile on any of the five index scores."
    If I model Mensa selection criteria as:
    X_1,…, X_5 ~ N(0,1)
    and Cor(X_i,X_j) = 0.8 for i !=j
    then P(max( X_1,…, X_5) > 2) ≃ 0.058
    The distribution is not normal but can be simulated. Additionally, if the rarity of the test score is used rather than the estimated g based on the g-loading of the test, it will necessarily overestimate people above the mean.
    Mensa justifies the choice as follows:
    "In fact, various scores are calculated and utilized between the RAIT and Wonderlic as qualification into Mensa to ensure additional fairness in IQ evaluation. We are also exploring the expansion of calculated quotients from six to seven to include a newly developed Nonverbal score for the RAIT. Ultimately, utilizing multiple score calculations within the RAIT reduces the likelihood of a false negative qualification into Mensa."
    Apparently, Mensa used to give multiple tests, including a matrix only test which is a noisier measure of g.
    I'd be more concerned about acceptance based on matrix only tests and childhood scores.
    I believe the choice of having lower entry requirements can be justified. What is the purpose of these societies? Scientific progress? Social interactions? Would it not be better to have a higher false positives compared to false negatives? I recommend the paper “Low base rates and a high IQ selection threshold prevented Terman from identifying future Nobelists”.

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    Replies
    1. Igor DSeptember 5, 2025 at 1:41 AM

      Hi, Kevin
      I actually reached this blog from ISPE facebook group, too. And I also took both the WAIS and RAPM (which was a qualification test to Mensa back in a day). From what I know Mensa accepts only FSIQ on the WAIS and not index scores. Please see the following link: https://www.us.mensa.org/join/testscores/
      It's true that there are societies that accept index scores (e.g. VIQ and PIQ in WAIS-III). The most famous one is Intertel (which may cause absurd situations such that a candidate cannot qualify for Mensa due to lower FSIQ but can qualify, for a more exclusive, Intertel due to VIQ or PIQ only). Can you please add the link to a page where it says that Mensa accepts index scores?

      Delete
    2. Igor DSeptember 5, 2025 at 1:45 AM

      Now I see that you mean the RAIT. It's interesting though that FSIQ is needed for the WAIS but index scores are accepted from the RAIT.

      Delete

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