The modern IQ tests have their origins in France, when teachers found themselves overwhelmed by the range of learning abilities they were presented with after the government passed a law that made school attendance mandatory for all children. They quickly realized that the schools needed a way to objectively identify which children had special learning needs. Relying on teachers’ subjective evaluations was not going to prove realiable, as struggles for certain children could merely reflect inadequate exposure to schooling, not an inability to learn or an inadequacy in terms of potential. The test then, was actually created to minimize bias. While I am not a fan of government controling any kind of educational assessments, I think it is important to note how these kinds of tests originated. They were meant to improve education by pinpointing needs, but what it has become is a way to label people with attributes and limitations, adults and children alike.
The “standard” IQ test is an adaptation of the one utilized in France over a century ago; it is called the Stanford-Binet test. The “Intelligence Quotient” as I am sure you know, is simply a person’s mental age divided by their chronological age ten multiplied by 100 to eliminate the decimal. The test, then, established “mental age” and the score came from plugging it into this formula (the formula originated out of Germany). What is interesting to note --an here’s where I question the validity of any test you can take online-- is that most professionally administered IQ tests no longer compute an “IQ,” not even the working version of the Stanford-Binet. The original quotient formula worked well with children. A smart child who could answer questions the way a typical child that was several years older than him would score higher. But did an adult who scores as well as an adult younger than them deserve to have a “low IQ,” especially once you got into the older ages of adulthood, because that’s what happened if you started plugging numbers into the formula. A sixty year old, then, would be numerically punished for scoring the same as a fifty year old, which seemed troublesome.
Psychology’s answer was to then evaluate the test-takers’ performance relative only to the average of others the same age, and they do this when testing both adults and children. Current tests, I believe, still define the average score as 100. What results, then, is “a mental ability score.” (they no longer like to use the word "quotient). Most people, using this age-restrictive evaluation, score between 85 and 115. I don’t know where you would start defining genius… as I still believe genius lies largely in action that the test cannot quantify. Sure, it may prove one is good at manipulating forms in space and doing math, but no score can really predict with 100% accuracy what any individual will do or accomplish. I think it should be used as an indicator, at best, and still does have value for pinpointing educational needs in children. Many of the assessments that I use in a primary level Montessori environment are very similar to components of the IQ test. But the number one method of evaluation I use is observation, for it is tthe children’s ability to move through a process that reveals where their struggles and their talents are. This is why I believe that IQ tests administered by someone who watches you move through the process can be more helpful as opposed to taking one online, especially if you’re really looking for insight about you r thinking abilities or have a desire to know how you compare to others. How you approach a problem can be just as insightful, if not more so, than the result you arrive at. One could argue that puts you at the mercy of the administrator’s subjective judgment of your process, but it really doesn’t. I recently took a “cognitive evaluation” (ie, an IQ test), and found that the explanations I was provided were not judgments so much as they were explanations of how my processing compared to those of others. The administrator never said, “you did it this way, so that makes you smart.” He explained it more along the lines of “you did it this way, whereas most people did it this way.” That was useful information to me. That is what I walked away remembering and thinking about. I was given a score, but it didn’t make me feel smart (even though it should have, considering what the average score is). What made me feel intelligent was understanding what my learning style was - visual - and how I used that to work through all sorts of different problems. There were no subjective evaluative statements involved. Just concrete and mathematical comparisons. The interpretation is really up to the individual, not the administrator, especially for someone taking the test just out of personal curiosity.
If you are taking tests online, I would at least try and see if the sites explain the formula they are using. As an adult, you want to make sure they are comparing your results only to people your own age; otherwise it might produce a misleadingly low or high score. Different tests are probably using different formulas, that could be one reason why one’s “score” could vary so widely from test to test.