I would be weary of anything that appears to, or claims to measure "intelligence" as it isn't something that is particularly easy to measure.
It is more of a problem of how "intelligence" is defined, really.
In psychometrics, they use
the g-factor.
In larger scale statistical analysis of IQ tests, it looks like there are at least three aspects to "intelligence": reasoning (logic), short-term memory, and language/verbal ability.
It looks like in general, IQ tests are
statistically reliable. That is, testing a single person using a single test should be treated as a single sample, and not a reliable indicator. However, applying several different tests should yield a more reliable picture of the general intelligence or cognitive abilities of that person.
(The way the tests are constructed, however, is such that each result is likely to be too low than too high. You'll see that in multiple-choice questions there are at least six options to choose from, to minimize the chance that picking choices by random gives a positive result. Then, there are more complex evaluation methods, similar to those used in psychological tests, where the combinations of choices are evaluated, instead of each question as a singleton.)
So, it's not that the IQ tests themselves are iffy per se; it's just that one must be critical of how to interpret the results.
And yes, this does mean that anyone who is a member of Mensa, does not understand statistics and/or psychometrics.
What if someone is aware of who they are speaking or writing for, and carefully chooses their words to communicate most effectively? Or conversely, if someone seems blissfully unaware and uses all the wrong words? Is that not a marker of intelligence (or lack of)?
I am socially inept: I tend to always communicate the same way. Does that reflect my lack of intelligence, or is it just a quirk of my personality?
My view is that social awareness of context, and applying it to communication, is
cleverness -- a skill, basically, that many learn as a kid -- rather than an indicator of intelligence.
(Example: Someone in a foreign country speaks their own language loudly and slowly in the assurance that the listeners must understand them if they speak slowly enough, while making no attempt to communicate in the local language used by the listeners.)
I've known one such person, decades ago. They were traveling outside Finland for the first time in their life. The tourists they had met in Finland had all knew a phrase or two of Finnish, out of a frase book I think (and speaking slowly and loudly and enunciating clearly of course helps then). They weren't stupid, just very, very inexperienced:
they didn't know any better.
On the other hand, even though they were old, they did learn key phrases quite quickly... like
"Una cerveza, por favor."So, still no from me: I think that is a social issue, nothing to do with intelligence per se. (Wrt. americans, inasmuch as that actually happens, I blame the perception of American Exceptionalism. Otherwise just us hicks let outside for the first time.)