> 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 litt

> 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.)