At one time, I had the spiffy title Director of Community Life for The TAG Project. So I was doing pro bono work in gifted education and was part of the fairly small online gifted community.
I attended a Beyond IQ conference and was a low level presenter. I met Kathi Kearney in person at the conference and she knew my name and backstory from our online interactions. I met the author and webmaster of Hoagies Gifted page who was also a board member for The TAG Project at a time when the founder was trying to turn it into a tax deductible registered charity, an effort later abandoned.
Long story short, I was something of an insider at one time and had insider information. I'm not an insider anymore and haven't been in years and when I try to look up stuff online to support statements I once understood to be common knowledge, I frequently cannot find any supporting citations.
In 1904, Binet took part in a commission set up by the French Ministry of Education to decide whether school children with learning difficulties should be sent to a special boarding school attached to a lunatic asylum, as advocated by the French psychiatrist and politician Désiré-Magloire Bourneville, or whether they should be educated in classes attached to regular schools as advocated by the Société libre pour l'étude psychologique de l'enfant (SLEPE) of which Binet was a member. There was also debate over who should decide whether a child was capable enough for regular education. Bourneville argued that a psychiatrist should do this based on a medical examination. Binet and Simon wanted this to be based on objective evidence. This was the beginning of the IQ test.
That's not exactly what I heard but it's closer than what I usually read these days. I heard that rural French children often didn't have birth certificates and they wanted a test for school readiness in an era when you couldn't reasonably use date of birth to determine it and urban children were much more likely to have firsthand experience with things like standing in line that helped prepare them for a public school environment.
The above is from the Wikipedia page about Alfred Binet and my recollection is the first IQ test was the Stanford-Binet. My French is not great. My interest in the topic is not sufficient to desperately try to find, read and attempt to understand original sources in French to check if my recollection of what I learned was correct or not.
Suffice it to say that it is my understanding that Binet did not set out to measure "intelligence" per se and IQ tests have substantial limitations and problems. The very concept of measuring general intelligence is rife with significant problems.
Back in the day, IQ tests typically topped out at 145. That's called the ceiling of the test and anyone hitting a test score of 145 probably had an IQ higher than that.
IQ tests are tools useful in the hands of a qualified professional. Taking an online IQ test is basically nonsense for funsies and not a meaningful result.
If you have an IQ above a certain point and are not tested by a qualified professional by, say, age seven, it can be impossible to actually determine a score.
All of the above points taken together mean that if someone tells you their IQ is above 145 AND they haven't been to the Gifted Development Center in Denver, Colorado or a similar professional organization for testing at a young age, they are full of shit.
IQ tests are culturally specific. This has a ZILLION problems from not being useful to test people from other countries with the same default language to having both classist and racist bias prone to reinforcing existing social problems.
As a very simple example, rural children who grow up on farms may learn seasons like "planting season" and "harvesting season" instead of winter, spring, summer and fall. A TEST may determine them to be ignorant of extremely basic knowledge and downright retarded (below average intelligence) because they are farm kids, not city kids.
This means anyone testing poorly who is a different race, culture, religion and a long list of other demographic categories than the dominant demographic -- upper class, citified, white collar, Christian white male in the US -- may be getting told they aren't that bright and don't have much potential and this becomes self fulfilling prophecy as they get gatekept out of good schools and good jobs etc etc etc.
IQ tests can be gamed. If you get hold of a test, you can look up the answers before trying to take the test. They stop being useful tools if they get leaked to the public.
IQ tests get stale. Because it's culturally specific, it's also specific to a particular era and time moves on and the younger generation stops having the same "common knowledge."
It's challenging to update IQ tests. When the old tests stop being relevant, it's not easy to whip up a new one to replace it.
Last I heard, they were working on developing a new IQ test and found that the results didn't really make it a good test of general intelligence but did make it a wonderful tool for identifying twice exceptional kids.
Richard Feynman's IQ score was supposedly only 124 or 125, yet he did phenomenally well on an obscure math test called The Putnam. This may be stronger commentary on the limitations of IQ tests than on the intelligence of a famed physicist who was very influential during his life.
Does that mean testing is worthless? Not necessarily.
When I met Kathi Kearney, she gave an example in her speech that an eleven year old testing at the senior in high school level was the intellectual equivalent of an 18 year old or an IQ of 180.
This hit a nerve for me because my oldest had tested at the senior in college level at age eleven on a test for determining curriculum needs at a charter school. So I asked her "What IQ equivalent would it be to test at senior in college level at age eleven?"
Professional ethics prevented her from giving me a number, but she recognized my name from our online interactions and replied "Oh, you poor thing. But it will be okay because you homeschool."
So I went back to my hotel room and called my sister to apologize to her for blowing her off when she previously suggested my kid probably had an IQ of at least 200. And I had a panic attack for about two hours about "How am I EVER going to cope with this kid!"
And then decided I already knew he had big strengths and big weaknesses, having "a number" gave me some perspective on how big those hills and valleys were, but I had been doing a fine job with him for nearly thirteen years and it would, in fact, be okay.
Footnote
I later learned the test my son took at age eleven where he tested at the senior in college level only went to senior in college level. So he ceilinged the test and even if Kathi Kearney had given me a number, it's not necessarily accurate. His IQ could be higher than that.
Also also: In addition to testing at high school or college level in some subjects, he tested below grade level in others.
No, he's not "generally" smarter than everyone else in all things.