It looks like you created the 2014 survey before I got around to posting my comment for this one. Oh well. Hopefully you will still find my comment useful. :)

Some answer choices from the survey weren't included in the results, without any explanation as to why. Does that mean no one selected them? If so, I suggest editing the post to make that clear.

I noticed that 13.6% of respondents chose not to answer the "vegetarian" question. I think it would have helped if you provided additional choices for "vegan" and "pescatarian".

Finally, at the end of the survey I had a question offering respondents a chance to cooperate (raising the value of a potential monetary prize to be given out by raffle to a random respondent) or defect (decreasing the value of the prize, but increasing their own chance of winning the raffle). 73% of effective altruists cooperated compared to 70% of others - an insignificant difference.

I have some doubts as to how good of a gauge this question is for altruism. People may choose to defect if they have immediate pressing needs for money, if they think their charity is superior to what most other people would have chosen, or if they don't see a net altruistic benefit in taking more money away from the prize-giver just to give it to a randomly selected survey-taker. I suppose if they bothered to think through it carefully they might have reasoned that all else being equal you'd prefer them to cooperate, which is why you're willing to give them more money for it. However, it could have also been that you saw the promise of extra money as a necessary sacrifice in order to set up the dilemma properly, but secretly wished for most people to defect. (Which one was it, by the way, if you don't mind me asking? :P)

I don't know for sure that Mensa is on the level, so I tried again deleting everyone who took a Mensa test - leaving just the people who could name-drop a well-known test or who knew it was administered by a psychologist in an official setting. This caused a precipitous drop all the way down to 138.

I think I know why removing the Mensa tests from the IQ results brought down the average. It's not because the Mensa test is unreliable, but because the people who bothered to take it are likely to have relatively higher IQs, in which case it would make sense to remove them from the sample to remove the bias.

People who spend more time on Less Wrong have lower IQs.

My guess is that lower IQ people may spend more time on LW because they derive more benefit from reading posts about rationality. Perhaps higher-IQ people are more likely to efficiently limit their time on LW to reading only the top-rated interesting-looking posts and the top-rated comments.

Height is, bizarrely, correlated with belief in the supernatural and global catastrophic risk.

Your data actually showed that height is anti-correlated with belief in the supernatural, unless that minus sign wasn't supposed to be there.

Thanks for posting these surveys and survey results, by the way. They are very fascinating. :)