When I started teaching every kid was given an IQ test and it was duly recorded on their accumulated file. It was a sacred number that told all kinds of things about a kid. In the rural school that I went to in the 40's IQ tests were given. Since the teacher went home for lunch, kids occasionally snooped through the desk. There was my IQ ...103! (Now if you couldn't get in the teacher's desk , how else would you put the mouse in the drawer?)
A form of IQ test is still given today.
When I started teaching the IQ was considered to have great validity. If a kid wasn't doing well, we'd check the IQ to see if there were any indications there. Should the student be achieving more?
One student had an IQ of 80. Teachers were naive enough to wonder how someone with an 80 IQ could do so well. Obviously something was wrong with the IQ result..
Do we have a definition of intelligence that can be measured?
As you can tell by now I'm definitely not a fan of IQ tests. There are too many very large variables. Tests were biased towards kids who could read. Kids who read well did well on IQs. Location influenced IQ. IQ tests were slanted toward urban kids. A little farm kid like me had never heard of some of the things on the test. The tests were not administered in standard ways. With my daughter, she was ill for the second part of the test and stayed home. The test was never completed. .Some method of prediction was used to complete her score. What about the little kid who wrote the test and didn't feel well?
Gradually educators began to see that there were holes in IQ tests and they were slowly phased out. In many places the actual number was erase.
Now I don't know what the MENSA people will think of me. I am criticizing their claim to being. To be in the Mensa club you have to have an IQ over a certain level.
Standardized tests are still used. Some of the bugs have been ironed out but they are not considered to be of great accuracy and are not used to make predictions.