That wasn't the point. I would say the same for 100 and 110.
Some MENSA members in this thread seem very attached to their scores.
That's the other thing, you do have to look at the whole. Because there is likely overlap. But the trend of note is that IQ tracks through it.
If you sort people by earning potential, you'll find that as average income goes up, so does average IQ.
When you sort by health outcomes. As average healthiness goes up, so does average IQ.
Even the outcomes that are colloquially contrasted with intelligence actually correlate well. In other words, if you sorted people by EQ, you'll find that better average EQ means better average IQ.
IQ is the aspartame of psychology. So maligned that it's been probably studied more than other things. And just like aspartame is perfectly fine, IQ does what it says on the tin.
100 vs 140 will be a very strong indicator. 100 vs 110 will not; I would not trust 110 to yield a better outcome 80-90% of the time, as GP claimed.
Which is why the comparison of IQ scores at that coarseness is plain silly.
On average, people raised in poor environments who have higher IQ do better than people raised in poor environments with lower IQ. More likely to be more upwardly mobile, more likely to be more whatever.
And on average, people raised in good environments who have higher IQ do better than people raised in good environments who have lower IQ.
If you're a person of color, on average, you're going to do better if you have a higher IQ than if you have a lower IQ.
Same if you're a woman.
And 140 vs 130 is a bit unfair. You're talking about looking for meaningful differences between less than 2% of the population as compared to less than 0.1% of the population.
And just because there are diminishing returns with something like IQ, doesn't make it useless.