I use IQ test.
Companies with over 25 employees would probably be sued if used that as a criterion.
Probably not a very smart way of hiring (oh, the irony).
Intelligence is so much more than a single number.
Someone of a lower relative IQ might be much better mechanically, logically, and at identifying creative solutions to mundane problems than a person with a higher IQ who displays flashes of brilliance re: higher level, pure mathematics, but cannot deal with mundane issues and may even become depressed with boring problems.
Conclusion: IQ may not be the best test of who can get a job done.