Let's pretend that each LWer represents a snapshot in the life of one big meta-uber-LWer. Here is the story of hisher life (with my theory in parentheses):
It starts off its life making less money than average, but donating more of their overall salary. (Perhaps an idealistic student who spends a large chunk of its early 20s in school. Since most of school ends up being paid for by Uber-Parents, it has more disposable income to donate.)
Once it reaches its mid-20s, it starts making more money than the average. But, on the downside, it starts donating a lot less both overall and as a percentage of its income. (That college education pays off with a decent job, but the reality of growing up sinks in... Bills must be paid, rent is due, groceries must be bought, and less money is available to give away.)
As it reaches its mid-30s, it advances its career sufficiently, and starts making pretty good money, but not millionaire money. (Now that it has a lot more money to throw around, it's safe to start being idealistic again. After all, it finally made it!)
Despite its success, the Uber-LWer is still making less money than the Uber-HighIQer. (Perhaps people are overreporting their IQ. Or maybe there's some social consequences to rationalism. Or maybe the career paths of LWers tend to be lower paying. Not sure what to make of this one.)
[edit] Incidentally, the US Mean Income shows us why we typically use Median income instead: the mean is dramatically thrown off by the small percentage of very rich individuals.
maybe the career paths of LWers tend to be lower paying.
I think so. Don't we have quite a lot of people in academia, for instance?
Oh, I guess the other thing is where one lives. Salaries are high in the US, and LW has plenty of people from elsewhere. (I think the difference is particularly large in the software industry, where lots of LW people and lots of high-IQ people work.) Do you fancy taking a look at what happens if you restrict the LW sample to people who live in the US?
[EDITED to add: Oops, I see ChristianKI has already made this observation.]
Note: Three data points were removed from the sample due to my subjective opinion that they were fake. Any self-reported IQs of 0 were removed. Any self-reported income of 0 was removed.
*89% of the LW population is between the age of 15 and 34.
**88% of the LW population has an IQ between 125 and 155, with an average IQ of 138.
****Median numbers were adjusted down by a factor of 1.15 to account for the fact that the source data was calculating household median income rather than individual median income.
[1] Internal Revenue Service, Charitable Giving by Households that Itemize Deductions (AGI and Itemized Contributions Summary by Zip, 2012), The Urban Institute, National Center for Charitable Statistics
[2] U.S. Census Bureau, Current Population Survey, 2013 and 2014 Annual Social and Economic Supplements.
[3] Do you have to be smart to be rich? The impact of IQ on wealth, income and financial distress Intelligence, Vol. 35, No. 5. (September 2007), by Jay L. Zagorsky
Update 1: Updated chart 1&2 to account for the fact that the source data was calculating household median income rather than individual income.
Update 2: Reverted Chart 1 back to original because I realized that the purpose was to compare LWers to those in similar income brackets. So in that situation, whether it's a household or an individual is not as relevant. It does penalize households to an extent because they have less money available to donate to charity because they're splitting their money three ways.
Update 3: Updated all charts to include data that is filtered for US only.