Buzz I do sympathise; I've just gone through the mill myself and have done around a dozen of these things over the last seven months of job hunting. I have an MBA from a top 20 in the world business school and finished in the top 10% of my class. The problem is that in life, you have to continually prove yourself; you don't get to do it just once and then sit back.
In relation to a design role, the validity of cognitive ability tests (this being the technical term for intelligence tests) is harder to understand but it can be a perfectly reasonable part of a company’s overall talent strategy to employ minimum scores.
Assessment for suitability is a highly technical subject and is driven largely by measurement and validity. The best approaches combine cognitive ability, experience/competency based interviews, motivational analysis and simulations to really assess accurately (anything over 0.4 correlation coefficient is regarded as being reasonably good, the best you can get to is 0.7 - I know the engineers now will be deriding these figures but it's an economic argument) a person's ability to do a role.
