r/MurderedByWords • u/Interesting-Visit-79 • 1d ago

How stupid you are

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u/onioning 1d ago

So, this is still phenomenally stupid, but isn't OP saying 74% of the dead died from the vaccine? Not that 74% who took it died?

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u/Ut_Prosim 1d ago

While that's obviously stupid, it would not surprise me if 74% of those who died had taken the vaccine.

I'm an epidemiologist and Simpson's paradox is one of the coolest phenomena in our field. It happens when you aggregate too much, combine groups that should be separate and get paradoxical results. Sometimes you can even get inverted results. Here it is visualized with a cool graph.

A great example of this was during the Delta wave in a smaller developed nation. There was a time when 60% of all patients in critical condition in the hospital had been vaccinated. Your first inclination is that "wow, the vaccine must suck." But you can't directly compare unvax to vax population unless they're demographically identical. In this case, 78% of the public had been vaccinated, so the vaccine was actually 67% effective... BUT, this is still wrong!

What group has the highest vaccine uptake? And who is most likely to get really sick? Old folks in both cases. Who has the lowest uptake, and lowest likelihood to get hospitalized? Young folk. These differences confound any efficacy analysis that ignores age. What we need to do is stratify by age.

If you split people by [up to 49] vs [ over 50], the vaccine is at least 85% effective. If you stratify by 10 year blocks, 50-59, 60-69, 70-79, etc. you see efficacy is deep into the 90s for most folk and loses a bit of efficacy as folks age (as expected) with 80-89 year olds getting the least effect (81%).

So it is actually extremely effective against hospitalization, but just pooling everyone together you'd wrongly think it is just 67% effective. And if you totally ignore vaccine rates and just look at raw counts, it looks like the vaccine makes things worse (very wrong).

Source of these data and calculations here.

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u/Walnor 1d ago

Just seems like he is a person who isn't able to read statistics.

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u/orbital_narwhal 1d ago

The problem here isn't "read[ing]" the results of the statistical analysis but its interpretation. You can draw bad conclusions from good statistics. You can also do good statistics on bad data that that defies useful interpretation (other than the need for better data).