IQ has a interesting property in which it is multiplicative at the individual level, but not additive at the individual or collective level.

A 140+ IQ person is not 40% smarter than a 100 IQ person, but much smarter. Someone with an IQ of 100 may struggle at college math but someone with an IQ of 140 can do cutting edge research.

Likewise, adding two 120 IQ people does not equal a 140 IQ person. So even a dozen 100 IQ people working together will not be able to solve a math problem that a single person who has an IQ of 140 can solve.

There is the hypothesis of lead causing increased crime rates: https://en.m.wikipedia.org/wiki/Lead–crime_hypothesis

At the risk of stating the obvious, IQ points aren't a measure and adding them up doesn't yield a meaningful number. It's like adding up the numbers on football player's jerseys; if the total of a team's numbers goes up, that doesn't make the team better. Similarly, a reduction in the total amount of "IQ points lost" could easily correspond to more damage to cognitive intelligence caused by lead exposure.

If you're looking for a sports analogy, I think it's sort of like "change in total seconds it takes the players to run the 100-yard dash". Not directly tied to success, and in some sense a pretty arbitrary measure, but a number that's nonetheless concerning to see get worse.

I agree IQ is a pretty bad measure. And if you would like to go back and redo this study with a better one, I'm sure we (and this study's authors) would be grateful for the result. But since it's the measure we have, I'd say it's better than nothing, and this factoid is a good way to spark interest in the scale of the phenomenon.

I think they're talking about measures in the mathematical sense. It measures something real, but a difference of one IQ point doesn't mean the same thing across the entire scale, so you can't just sum IQ point differences.

Actually an amazing sports analogy. IQ is basically a metric same as any other startup metric. You can’t expect it to tell the whole story but it’s one useful thing that can be measured.

you are comparing something entirely cosmetic to something that is predictive and of real consequence

>> This amounted to a total loss of 824,097,690 IQ points, disproportionately endured by those born between 1951 and 1980

> At the risk of stating the obvious, IQ points aren't a measure and adding them up doesn't yield a meaningful number. It's like adding up the numbers on football player's jerseys; if the total of a team's numbers goes up, that doesn't make the team better. Similarly, a reduction in the total amount of "IQ points lost" could easily correspond to more damage to cognitive intelligence caused by lead exposure.

This is how I read it when I saw this number based on the title (I didn't read the article):

There are about 300 million people in total. Half of that is 150 million. A loss of 824,097,690 IQ points over 150 million people is over five point per person.

https://www.google.com/search?q=824%2C097%2C690+%2F+150+mill...

This is, of course, extremely misleading because someone born in the late eighties didn't suffer the same as someone born in the sixties. Similarly, someone born on or after January 1, 1996 didn't suffer as much as someone born in the eighties. Therefore, "five points per person" would be more misleading.

At the end, the actual number doesn't matter much. What matters is that the number conveys a sense of magnitude. We collectively lost almost a billion IQ points!

It doesn't matter what it exactly means. We just need to know that "they" robbed us. When I say us, it isn't just those of us in the US, I mean the whole world as the baby boomers voted and continue to vote (older people are more likely to vote compared to younger people). Who knows maybe if we had higher IQ, we wouldn't have fallen for nonsense like "starve the beast". If you stop to think for two seconds, reducing income because you think you are spending too much is asinine. It doesn't matter whether it is the federal government or a small family, it makes no sense to say well I am spending too much but if I had less income maybe my expenses would suddenly come under control.

Maybe with a slightly higher IQ, the people who voted in the eighties would have demanded this nonsense be nipped in the bud. I can't even imagine how much of a better place the world could be if we took a different path instead of following Ronald Reagan's shenanigans.

> What matters is that the number conveys a sense of magnitude. We collectively lost almost a billion IQ points!

But losing a billion IQ points might be less bad than losing 10M IQ points, because there is literally no scale.

> But losing a billion IQ points might be less bad than losing 10M IQ points, because there is literally no scale.

Maybe there is a bigger point I don't understand here (wouldn't that be ironic) but I only have about a hundred IQ points to play with and so does the average person (by definition?) so a billion IQ points is all the IQ points for ten million "average" people.

What am I missing?

You probably wouldn't detect it since there are so many effects at play here. For example, the parents of those born after WW2 in western countries are on average much younger than before (especially men) or after. Parental age has a significant effect on mutation rate and hence mental illness. As a consequence, bare intelligence is slightly increased in the same generation.

Also this article in Mother Jones: https://www.motherjones.com/environment/2016/02/lead-exposur...

> That is interesting, but what I really wonder about is more subtle cognitive effects. Did it make people meaner? More easily led? Less collaborative?

More boomer for sure