[MattyMc]

> Anyone who doesn't understand this is an idiot imo

I don’t think that’s true. Avoiding this mistake requires knowing that an ultrasound may not detect calcification. For a patient reading their own report, I don’t think that’s intuitive. I would expect most people to read “no calcifications” and assume that their joint has no calcifications.

[nkrisc]

Most people should have learned at a young age that absence of evidence is not evidence of absence. My 8 year old understands this. After all, you can rarely ever prove something does not exist, only that it is unlikely to exist.

If a report states that X was not found, it does not mean X did not exist, it means it was not found.

What may be lost on the layperson is the nuance and understanding of how thorough or not a particular scan is and how much weight to give the findings and thus the odds that the report is correct.

[aforwardslash]

This is - by far - the most stupid stuff I've read on the internet the past few days. They didnt find cancer either (as well as a plethora of diseases that could be related to the symptoms), and afaik its not in the report.

Yah you can argue that the tool is not ideal for that diagnostic, yadda yadda. I get it, and in the end I agree with the subtle difference you highlight, because it is something that makes sense to a certain kind of people. You know how many medics would read the report exactly like the author did? Too many.

How do I know? Im not in a wheelchair after being constantly misdiagnosed by using the wrong imagiology technique by (mostly) chance, and a good help from friends, including a surgeon. This seems to be a case where AI would be a valuable doctor tool for differential diagnosis; instead we have know-it-alls that can't bother to verify, and AI that often gets details wrong. That is the problem.

[Fr0styMatt88]

I think it’s the combined depth AND breadth of knowledge that can be captured by AI models that is going to make them way better than most humans at this kind of stuff.

[Sabinus]

It's like when finding out about the sex of your baby via ultrasound before they're born. If you're told it's a boy, you can be pretty certain you're getting a boy. If you're told it's a girl, you shouldn't get too attached to the idea. The ultrasound tech might just have missed the evidence your baby was a boy.

[sjducb]

> Most people should have learned at a young age that absence of evidence is not evidence of absence.

I’m fairly sure that there are no lions in my house. Lions are quite large and I’m capable of detecting lion sized objects with my eyes.

To demonstrate that something is not present you first define the object, then come up with a test that will reliably detect the object. If the test comes back negative then the object is not there.

In a strict philosophical sense I cannot prove that there are no lions in my house, the external world might not exist! A hypothesis that no one has thought of might be correct and that hypothesis could show that there are invisible lions in my house!

However I intend to act with the certainty that there are no lions in my house. Because I have no evidence of lions in my house.

Absence of evidence is evidence of absence.

[ytoawwhra92]

"Calcifications not found" is a different statement from "no calcifications".

Even then, the context that "ultrasound isn't a great way to assess for calcification" is important when reading either statement. Laypeople don't necessarily have that context.

[mewpmewp2]

But the problem was that the report is not saying "not found", it is saying "is not present" or "there is no X".

And I think we can easily have examples where we can reasonably trust this, and a spectrum of such.

E.g. there is a math solution and the report says "there is no errors in this solution", you would imagine that to be quite reliable, no?

[O_H_E]

> Most people should have learned at a young age that absence of evidence is not evidence of absence.

That might be true, but it is definitely not the world we live in.

[Fr0styMatt88]

Exactly. I was about to reply to the comment with “perfect example of not knowing what you don’t know” in terms of self-diagnosis.

My internal model is/was “if the scan wasn’t set up / can’t detect the thing, why would the statement be present at all?”.

That implicit assumption is really subtle.

[tomlockwood]

It's a fatal flaw to think counter-intuitive == wrong.

[eqmvii]

It’s 2026 and my computer will happily give me the right answer even when i make typos. I love it.

[ambicapter]

Not really, it just requires to assume an ultrasound has infinite, perfect resolution when you are faced with a different imaging tech which reports things that didn't appear in the first one. That's just stupid.