Episode 57: Collider bias

13 snips

Nov 26, 2024

This discussion dives into the perplexing phenomenon of collider bias in health studies. It reveals surprising findings, like hospitalized COVID patients who smoke showing better outcomes. The hosts explore how obesity may correlate with improved survival rates in chronic diseases, challenging conventional wisdom. With humor, they tackle misleading correlations in both health research and sports, emphasizing the importance of context. The episode further questions the validity of standardized testing in predicting success, shedding light on deeper insights into merit and health.

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ANECDOTE

COVID-19 and Smoking Paradox

Studies show smokers had better outcomes with COVID-19 than the general population.
French doctors even handed out nicotine patches, misinterpreting the correlation.

ANECDOTE

Obesity Paradox

Obesity is linked to improved survival among patients with various diseases, including cardiovascular issues.
This is despite obesity being generally associated with increased mortality.

INSIGHT

Collider Bias Explained

Collider bias occurs when selecting for a specific group creates a correlation where none exists.
It's like a confounder in reverse.

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Among patients hospitalized for COVID, smokers had better outcomes. Among people with cardiovascular disease, those with obesity live longer. Among NBA basketballers, taller players don’t do any better. These are all facts. But the interpretation you might immediately draw is completely wrong.

It turns out that these findings (and many more) might be due to the weird and under-discussed phenomenon of “collider bias”. Everyone who’s interested in scientific methods knows what a confounder is—but do they know what a collider is? In this episode of The Studies Show, Tom and Stuart attempt to explain.

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Show notes

* French study on COVID and smoking rates

* French doctors handing out nicotine patches during the pandemic

* Review of 13 studies in China showing lower smoking rates in those hospitalised for COVID

* Among heart attack sufferers, smokers have better subsequent health

* Obesity linked to improved survival among patients with a wide range of diseases

* Within the NBA, tall basketball players do no better than short ones

* Standardized testing doesn’t predict how well graduate physics students do

* The same but for biology

* The same but for STEM in general

* Do neurotic people actually live longer, once you correct for self-rated health?

* Julia Rohrer’s blog article on collider bias, using the conscientiousness/IQ relation

* The “collider scope” paper - one of the best explanations of the phenomenon

* Article on “the obsesity paradox”

* Follow-up arguing that it might not be a paradox at all

Credits

The Studies Show is produced by Julian Mayers at Yada Yada Productions.

This is a public episode. If you'd like to discuss this with other subscribers or get access to bonus episodes, visit www.thestudiesshowpod.com/subscribe