How many different types of IQ tests are there and how do they vary from each other?
There are countless numbers of IQ tests available, with varying amounts of validity. The main ones in use, however, include:
WISC-IV (children) WAIS-III (by far the most commonly used) Stanford-Binet-IV RIAS UNIT WASI Woodcock-Johnson-R WPPSI (young children) KBIT DAS (children)
These differ in the theoretical basis used to develop the instrument, the validity and reliability, the subscores generated, and the length of administration. In general, IQ tests will give you a verbal intelligence score and a nonverbal/performance intelligence score, with further specifics varying by test. The UNIT is a nonverbal test (suitable for deaf or non-english-speaking individuals). The WASI and RIAS are brief forms (however, unlike the WASI, the RIAS is considered a full-scale IQ and not a screener)....they take approximately 20 min, vs. the 1 to 1 1/2 hours required for a full test.
Strictly speaking, intelligence tests only measure "ability." Any test that assesses writing skills, reading skills, math skills, etc is NOT an intelligence test, but an *ACHIEVEMENT* test. Comprehensive batteries will include both, as will assessments geared toward looking at learning disabilities.
Hope this helps!
The first answer was a good one. I just want to ad that pseudo-scientific "IQ" tests are used by some organizations to manipulate people. Be very suspicious when someone wants to test your "IQ".