IQ Tests in general

[frozennotes]

Hi all,

I've used the board search but did not come up with any results that would suit my question.
For a couple of months I've been wondering about how exactly the internal principles of an IQ test work.

I'll assume an average test with a mean of 100 and a ceiling of 145-149 as an example.
I took several of those on the internet, making sure that each lasted 45 minutes or longer and
made a professional, well-rounded appearance. My results were between 126 and 141.
Now to the question: While the ceiling of most of these tests was around 140, I always got results
in the high 120s due to me missing a handful of questions. Reviewing the individual tests revealed
that the items I got wrong were not significantly more difficult than the surrounding ones.

So if the average IQ test is, in it's respective subcategories, not based on progressively harder items,
how does an IQ test provide accurate differentiation between a score of 120 and one of 140?
What guarantees that a subject would not get a significantly higher or lower score a week later?

[frozennotes]

My second question is: How is it that the vast majority of IQ tests have their ceiling in the mid 140s?
I consequently wonder how people achieve scores in the 150s, 160s and even higher. I know that it
is possible for highly bright individuals to achieve scores in excess of 200 on the old Stanford-Binet while
they're in a certain stage of their childhood, but I also know that there are many more highly gifted people
with IQs in the neighborhood of 170 and upwards than most people realize.
What kind of test did those people use to obtain their score? And, do they always claim ratio IQs?
As a last question, I apologize for this mass of them, what is the highest deviation IQ achieved to date,
what was the subjects age, and what was the test employed?

sincere regards
frozennotes

[gone]

The IQ test aren't a reliable system for measuring intelligence. The ones in use aren't taken seriously anymore as they only test for a certain type of intelligence.

For example:
Woman A needs new brake pads on her car but can't afford the garage fees. She buys a book 'How to change your break pads' and purchases the parts and does the job herself for a fraction of the cost.

Woman B needs new break pads on her car but can't afford the garage fees. She asks everyone she knows if they know a mechanic, then one one is located she organises an event & makes sure he attends, she flirts with him an ultimately get's him to change her break pads.

Both women had the same problem, both women got the same result although by different means. Who's more intelligent woman A or woman B?

The popular IQ test, test for a certain type of person, they don't include things like 'spacial intelligence, dexteriety, independent thinking, creativity in problem solving etc etc etc.