Simpson's paradox

I once encountered this in the real world as a data analyst a long time ago. I was working at an e-commerce company, called The Hut Group, and the whole year our marketing team had been saying our marketing cost of goods sold (the percentage of our revenue we needed to spend on marketing) had been declining across every product category. But at year end, the execs were shocked to realize that our cost of goods sold had almost doubled…

This should be part of a required reading regimen for anyone about to post yet another 'Bullshit Study Reveals Whimsical Quirk' article.

This showed up in a recent (short) New Yorker article https://www.newyorker.com/magazine/2022/01/17/dinner-drinks-... > The first course of math, delivered during the first course of dinner (a scattering of salads), was a statistics starter called Simpson’s paradox, which explains how apparent biases in large samples can disappear in smaller ones. A famous example: For the University of California at Berkeley’s graduate programs in 1975, over all, men were admitted at a higher rate than women, but, program by…

Submitted because I see a lot of people hitting Simpson's Paradox in the various COVID vaccination discussions here, especially when looking at the data from Israel.