Please explain the difference between the newer and older IQ tests.?

Question

I'm too lazy to look it up right now and I wonder. I read here that the top score on the newer *standard* test is 150. How would that compare to a higher score on the old *standard* test? Are the lower scores more limited, also?

And I really don't need to hear about how culturally biased, meaningless or unreliable the tests are; that's a whole different issue.

Also, do scores tend to get lower with age, as the potential is less? Or am I misunderstanding that?

Answer 1

The highest score you can earn on the most recent Wechsler Adult Intelligence Scale is 155. Although, if you go by standard deviation both the Stanford-Binet and WAIS highest scores could be 160 (4 SD above the mean).
I do not know what the high score was with the original Wechsler-Bellvue Intelligence Scale. I know that in the 67 years since the first Wechsler test was published, it has been renormed several times. Over the years they have added a higher IQ ceiling (highest score). Its difficult to say what someone's score would be on the older tests, unless they were administered the WAIS-III and the older editions. Even then, there would be reliability and practice effects issues. Over the years, they have changed the way IQ is measured. With the culturally biased material (yes, I know you didn't want to hear about that, but its true), overreliance on timed performance, invalid test measures, and lower ceilings on the previous tests, then I believe their score would be lower on the older versions.
In theory, IQ should remain relatively stable over a lifetime, however, with dementia and normal cognitive and motor decline, I imagine IQ would decrease as a person ages (particularly in Working Memory and Performance subtests).