[_fat_santa]

My issue with this study is they based it around IQ points. I feel like IQ is a very bad measure of cognitive ability outside of determining if someone is competent of not. And the fact that it only went down by a mean of 5.5, I feel like that small of a decline could be attributed to someone just having a bad day or being a little groggy when they took the IQ test.

Had the measured brain waves or brain activity it would be one thing, but I feel like an IQ test is just not satisfactory for a study like this.

[dash2]

Have you got any reason to think IQ is a bad measure of cognitive ability? And what makes you think 5.5 points is small? The average is 100 and a typical standard deviation is about 15; one third of a standard deviation looks pretty big to me.

[troydavis]

> And the fact that it only went down by a mean of 5.5, I feel like that small of a decline could be attributed to someone just having a bad day or being a little groggy when they took the IQ test.

How does your theory explain that the results were particular to certain sub-groups? That is, the 5 point decline was only associated with long-term cannabis users.

(Is your theory that long-term cannabis users are more likely to "have a bad day or be a little groggy"? That would explain the sub-group difference, but it seems pretty similar to the author's results.)

[rcme]

5.5 is a massive decline in IQ.