I can account for this bias by looking only at the people who said they were ≥29 years old.* Among that older group, only 13% had a high school education or less...but the mean IQ of that 13% was even higher at 139.6, almost equal to the mean IQ of 140.0 for older LWers in general.
And I suspect if you look at the American population for that age cohort, you’ll find a lot higher a percentage than 13% which have a “high school education or less”… All you’ve shown is that of the highschool-educated populace, LW attracts the most intelligent end, the people who are the dropouts for whatever reason. Which for high-IQ people is not that uncommon (and one reason the generic education/IQ correlation isn’t close to unity). LW filters for IQ and so only smart highschool dropouts bother to hang out here? Hardly a daring or special pleading sort of suggestion. And if we take your reasoning at face-value that the general population-wide IQ/education correlate must hold here, it would suggest that there would be hardly any autodidacts on LW (clearly not the case), such as our leading ‘high school education or less’ member, Eliezer Yudkowsky.
All you’ve shown is that of the highschool-educated populace, LW attracts the most intelligent end, the people who are the dropouts for whatever reason.
Right, but even among LWers I’d still expect the dropouts to have a lower average IQ if all that’s going on here is selection by IQ. Sketch the diagram. Put down an x-axis (representing education) and a y-axis (IQ). Put a big slanted ellipse over the x-axis to represent everyone aged 29+.
Now (crudely, granted) model the selection by IQ by cutting horizontally through the ellipse somewhere above its centroid. Then split the sample that’s above the horizontal line by drawing a vertical line. That’s the boundary between the high-school-or-less group and everyone else. Forget about everyone below the horizontal line because they’re winnowed out. That leaves group A (the high-IQ people with less education) and group B (the high-IQ people with more).
Even with the filtering, group A is visibly going to have a lower average IQ than B. So even though A comprises “the most intelligent end” of the less educated group, there remains a lingering correlation between education level and IQ in the high-IQ sample; A scores less than B. The correlation won’t be as strong as the general population-wide correlation you refer to, but an attenuated correlation is still a correlation.
And I suspect if you look at the American population for that age cohort, you’ll find a lot higher a percentage than 13% which have a “high school education or less”… All you’ve shown is that of the highschool-educated populace, LW attracts the most intelligent end, the people who are the dropouts for whatever reason. Which for high-IQ people is not that uncommon (and one reason the generic education/IQ correlation isn’t close to unity). LW filters for IQ and so only smart highschool dropouts bother to hang out here? Hardly a daring or special pleading sort of suggestion. And if we take your reasoning at face-value that the general population-wide IQ/education correlate must hold here, it would suggest that there would be hardly any autodidacts on LW (clearly not the case), such as our leading ‘high school education or less’ member, Eliezer Yudkowsky.
Right, but even among LWers I’d still expect the dropouts to have a lower average IQ if all that’s going on here is selection by IQ. Sketch the diagram. Put down an x-axis (representing education) and a y-axis (IQ). Put a big slanted ellipse over the x-axis to represent everyone aged 29+.
Now (crudely, granted) model the selection by IQ by cutting horizontally through the ellipse somewhere above its centroid. Then split the sample that’s above the horizontal line by drawing a vertical line. That’s the boundary between the high-school-or-less group and everyone else. Forget about everyone below the horizontal line because they’re winnowed out. That leaves group A (the high-IQ people with less education) and group B (the high-IQ people with more).
Even with the filtering, group A is visibly going to have a lower average IQ than B. So even though A comprises “the most intelligent end” of the less educated group, there remains a lingering correlation between education level and IQ in the high-IQ sample; A scores less than B. The correlation won’t be as strong as the general population-wide correlation you refer to, but an attenuated correlation is still a correlation.