The mean IQ reported in the latest LW survey will be 137 or less (probability 75%).
Thought I'd squeeze that in before Yvain posts the results. Some background. In the 2012 survey LWers reported having a mean IQ of 138.7. I found (and find) that unlikely, and reckon that average was inflated through a mixture of selective reporting, mis-remembering, perhaps the occasional lie, and people taking old or otherwise iffy tests. However, the 2013 survey should suffer much less from that last problem because (if I remember rightly) it asks only about formally assessed IQs. So I expect the 2013 IQ average to be less (because less inflated) than the 2012 IQ average.
I'm not super confident about this, because there's some countervailing evidence (using self-reported SAT & ACT scores from the 2012 survey as IQ proxies suggests higher IQ estimates, not lower estimates), and because a selection effect could actually worsen the inflation in the 2013 survey (people with higher IQs might be more likely to have their IQs formally tested; if so, asking only for properly measured IQs will selectively pick out high-IQ people). But my hunch is that these issues won't matter so much.
A 138 average doesn't seem far-fetched at all to me. A little bit of self-serving bias is inevitable, but I highly doubt the real average is e.g. in the 120s. This random website I found says that the average IQ of an Ivy League student is 142. I go to a school that isn't as good as most Ivys but is better than some of them. I would guess the average IQ of a student here is 135-ish. The average LW poster seems much, much smarter to me than the average person at my school.
It's time to look back to see what was predicted a year ago and how successfully it was.
But even more, it's time for the fresh predictions for the following year, 2014.