How reliable and valid are online IQ tests?

Seems to me that if you use the brain you got...you can do the work of a genius. Just don't give up.

In theory IQ scores are not supposed to change with either age or education although they may vary for a number of reasons. Some students give up, others are ill or nervous when they take the test. Some say that they are culturally or sexually biased. Many believe that IQ scores are not valid. That is they do not measure what they are supposed to measure. My own view is that they are valuable and that a high score does indicate intelligence and that a low score may be incorrect for the reasons mentioned above. Some IQ tests are more reliable than others. You took two different tests and that may be one reason for the discrepancy in you scores. Don't worry about it. Don't be fixated on the IQ test itself. Do as well as you can in school and lead a well rounded and healthy life.

Your IQ score will differ on different tests. It just depends on what aspect and how broad the test is. IQ is not a single strength. It covers visio spatial, maths and verbal ability along with a whole host of other reasoning and cognitive areas. If you try Mensa you will find you are given a variety of timed tests on different aspects of IQ to give a properly measured IQ. IQ tests show a level of thinking and a potential but it does not measure academic ability. If you have a high IQ then you have the potential to go places and attain thing but it is still related to the effort you are prepared to put in!!!

about as reliable as other stuff you find online. it may be the cynic in me, but I wouldn't put to much stock into the tickle.com tests. If you do them, do them for fun.

They are neither reliable nor valid. Take the higher number -- it may mean you answered one question better than before.