Where’s that coming from? I didn’t read the paper yet, but the article says: “A secondary analysis also offers another silver lining, Gupta said. When the investigators compared just the 42% of participants in the invited group who actually showed up for a colonoscopy to the control group, they saw about a 30% reduction in colon cancer risk and a 50% reduction in colon cancer death.“

> This completely breaks randomization and is subject to investigator bias

Yes, true. I agree with you. This is important when asking the question “how effective is recommending screenings”. But, voluntary opt-in also breaks randomization, and is subject to patient bias.

> you’d need to test 667 people to save one life. That’s a lot of pain for very little gain

Assuming that’s accurate (the article appears to disagree), I’d still be very hard-pressed to agree with this conclusion. Why is a once or twice a decade doctor’s visit spread out over many people amounting to enough pain to let someone die? How much is a life worth? Is the colonoscopy really so bad that you’re willing to risk a greater than one in a thousand chance of dying? That risk is comparable to many extreme sports.

The problem with this kind of sum up the cost and make it look large is that you didn’t do this for anything else and compare it for reference, which makes this framing prone to cognitive bias. We spend billions and have laws for keeping drivers safe, for example. You could make it look insane by adding up the billions of dollars and people-years people spent bucking and unbuckling seatbelts, but the truth is that it’s a teeny inconvenience per person for a sizeable gain in safety and reduction in the accumulated secondary costs of accidental death.