Several people cited the AHS-2 as a pseudo-RCT that supported veganism (EDIT 2023-10-03: as superior to low meat omnivorism).
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My complaint is that the study was presented as strong evidence in one direction, when it’s both very weak and, if you treat it as strong, points in a different direction than reported
[Note: this comment was edited heavily after people replied to it.]
I think this is wrong in a few ways:
1. None of the comments referred to “low meat omnivorism.” AHS-2 had a “semi-vegetarian” category composed of people who eat meat in low quantities, but none of the comments referred to it
2. The study indeed found that vegans had lower mortality than omnivores (the hazard ratio was 0.85 (95% CI, 0.73–1.01)); your post makes it sound like it’s the opposite by saying that the association “points in a different direction than reported.” I think what you mean to say is that vegan diets were not the best option if we look only at the point estimates of the study, because pescatariansim was very slightly better. But the confidence intervals were wide and overlapped too much for us to say with confidence which diet was better.
Here’s a hypothetical scenario. Suppose a hypertension medication trial finds that Presotex monotherapy reduced stroke incidence by 34%. The trial also finds that Systovar monotherapy decreased the incidence of stroke by 40%, though the confidence intervals were very similar to Presotex’s.
Now suppose Bob learns this information and tells Chloe: “Alice said something misleading about Presotex. She said that a trial supported Prestotex monotherapy for stroke prevention, but the evidence pointed in a different direction than she reported.”
I think Chloe would likely come out with the wrong impression about Presotex.
3. My comment, which you refer to in this section, didn’t describe the AHS-2 as having RCT-like characteristics. I just thought it was a good observational study. A person I quoted in my comment (Froolow) was originally the person who mistakenly described it as a quasi-RCT (in another post I had not read at the time), but Froolow’s comment that I quoted didn’t describe it as such, and I thought it made sense without that assumption.
4. Froolow’s comment and mine were both careful to notice that the study findings are weak and consistent with veganism having no effect on lifespan. I don’t see how they presented it as strong evidence.
[Note: I deleted a previous comment making those points and am re-posting a reworded version.]
Getting the paper author on EAF did seem like an unreasonable stroke of good luck.
I wrote out my full thoughts here, before I saw your response, but the above captures a lot of it. The data in the paper is very different than what you described. I think it was especially misleading to give all the caveats you did without mentioning that pescetarianism tied with veganism in men, and surpassed it for women.
I expect people to read the threads that they are linking to if they are claiming someone is misguided, and I do not think that you did that.
You edited your parent comment significantly in such a way that my response no longer makes sense. In particular, you had said that Elizabeth summarizing this comment thread as someone else being misleading was itself misleading.
In my opinion, editing your own content in this way without indicating that this is what you have done is dishonest and a breach of internet etiquette. If you wanted to do this in a more appropriate way, you might say something like “Whoops, I meant X. I’ll edit the parent comment to say so.” and then edit the parent comment to say X and include some disclaimer like “Edited to address Y”
Okay, onto your actual comment. That link does indicate that you have read Elizabeth’s comment, although I remain confused about why your unedited parent comment expressed disbelief about Elizabeth’s summary of that thread as claiming that someone else was misleading.
[Note: this comment was edited heavily after people replied to it.]
I think this is wrong in a few ways:
1. None of the comments referred to “low meat omnivorism.” AHS-2 had a “semi-vegetarian” category composed of people who eat meat in low quantities, but none of the comments referred to it
2. The study indeed found that vegans had lower mortality than omnivores (the hazard ratio was 0.85 (95% CI, 0.73–1.01)); your post makes it sound like it’s the opposite by saying that the association “points in a different direction than reported.” I think what you mean to say is that vegan diets were not the best option if we look only at the point estimates of the study, because pescatariansim was very slightly better. But the confidence intervals were wide and overlapped too much for us to say with confidence which diet was better.
Here’s a hypothetical scenario. Suppose a hypertension medication trial finds that Presotex monotherapy reduced stroke incidence by 34%. The trial also finds that Systovar monotherapy decreased the incidence of stroke by 40%, though the confidence intervals were very similar to Presotex’s.
Now suppose Bob learns this information and tells Chloe: “Alice said something misleading about Presotex. She said that a trial supported Prestotex monotherapy for stroke prevention, but the evidence pointed in a different direction than she reported.”
I think Chloe would likely come out with the wrong impression about Presotex.
3. My comment, which you refer to in this section, didn’t describe the AHS-2 as having RCT-like characteristics. I just thought it was a good observational study. A person I quoted in my comment (Froolow) was originally the person who mistakenly described it as a quasi-RCT (in another post I had not read at the time), but Froolow’s comment that I quoted didn’t describe it as such, and I thought it made sense without that assumption.
4. Froolow’s comment and mine were both careful to notice that the study findings are weak and consistent with veganism having no effect on lifespan. I don’t see how they presented it as strong evidence.
[Note: I deleted a previous comment making those points and am re-posting a reworded version.]
In the comment thread you linked, Elizabeth stated outright what she found misleading: https://forum.effectivealtruism.org/posts/3Lv4NyFm2aohRKJCH/change-my-mind-veganism-entails-trade-offs-and-health-is-one?commentId=mYwzeJijWdzZw2aAg
I expect people to read the threads that they are linking to if they are claiming someone is misguided, and I do not think that you did that.
See this comment.
You edited your parent comment significantly in such a way that my response no longer makes sense. In particular, you had said that Elizabeth summarizing this comment thread as someone else being misleading was itself misleading.
In my opinion, editing your own content in this way without indicating that this is what you have done is dishonest and a breach of internet etiquette. If you wanted to do this in a more appropriate way, you might say something like “Whoops, I meant X. I’ll edit the parent comment to say so.” and then edit the parent comment to say X and include some disclaimer like “Edited to address Y”
Okay, onto your actual comment. That link does indicate that you have read Elizabeth’s comment, although I remain confused about why your unedited parent comment expressed disbelief about Elizabeth’s summary of that thread as claiming that someone else was misleading.
Hi, that was an oversight, I’ve edited it now.