Hi Abhi. Thanks for sharing.

Are you considering the risk of research on alternative proteins decreasing the welfare of farmed animals by decreasing the population of farmed animals with positive lives? I estimated cage-free layers and slower growth broilers have negative, but close to neutral lives. I am reasonably confident that caged layers and fast growth broilers have negative lives, but very uncertain about other cases. Here is an example of why this may matter in the context of eggs. 64.3 % (= 1 - 0.357) of layers in the European Union (EU) were outside cages in 2025. Funding work on alternative proteins does not have an immediate effect. It could be that it mostly reduces the consumption of eggs in 10 years, when the fraction of cage-free layers will likely be higher, and mortality lower due to improvements from experience. So I can see research on plant-based alternatives to eggs leading to fewer layers in the EU with positive lives.

Hi Matthew. Great post. I really like combinations of numbers and story-telling. I think they are a core motivation for people getting involved in effective giving.

Hi Huw. Thanks for sharing.

A vast and rapid injection of surplus labour into the global economy is potentially very bad

It is worth noting the speed and scope of an injection of surplus labour is not independent from how it impacts people. I am sceptical of a vast and rapid injection. However, if it happens, I would still expect it to be good.

I remain open to bets against short timelines for transformative AI (TAI), or what they supposedly imply, up to 10 k$.

Thanks for sharing your thoughts.

Thanks for your suggestion on how to present CEAs, we'll think about this further.

Great.

• I think that existing disagregated (non scaled) metrics already allow us to make reasonable guesses for what is cost effective to help animals.

A greater spread of pain intensities would update me (at the margin) towards prioritising very painful welfare issues happening over a short time (in particular, just before slaughter) over less painful ones affecting the whole life of animals

I also wonder whether there are cases where the time in less intense pain is decreased cost-effectively, but the time in more intense pain is increased. In such cases, one would have to rely on views about pain intensities to determine whether there is a reduction in pain. The Welfare Footprint Institute (WFI) estimates that cage-free layers experience less annoying and hurtful pain than ones in furnished cages, but that it is unclear whether they experience more or less disabling and excruciating pain. "The analysis primarily aimed to estimate the minimum welfare improvement associated with transitioning to cage-free housing". So it could be that cage-free layers also experience less disabling and excruciating pain. However, if this remains unclear accounting for all welfare issues as accurately as possible, and one believes disabling and excruciating pain are much more intense than annoying and hurtful pain, it could be unclear whether cage-free egg campaigns decrease or increase pain.

• I am not confident that we will ever gain lots of clarity on scaling, as there are lots of known unknowns and reasonable disagreements on questions up and downstream from how to scale things (sentience, range, etc.)

I am also not confident. However, I think there is high value of information in making at least one good attempt to quantify the intensity of excruciating pain.

Given the subjective nature of pain, I am not convinced a survey sampling from such a specific group is particularly externally valid (I also don't know that any survey of humans will ever be externally valid to how we'd scale pain across other animals).

I agree comparisons across different pain intensities and species will remain very uncertain.

I replied to the last link here

I replied there.

I think we should aim to have secondary effects of interventions

Great to know. Do you have any concrete plans or timelines? If not, how much funding would you need?

Nitpick. I would not call effects on non-target individuals "secondary". I think they may be much larger than those on the target individuals (in expectation), and "secundary" makes it sound like they are less important to consider.

I want to do it in a way that doesn't unnecessarily penalize/reward areas where that data is/is not available

Makes sense.

and to not have the effects of all interventions be dominated by deeply uncertain secondary impacts

What if, given reasonable moral and empirical views, we should in fact be very uncertain about whether practically any intervention is better or worse than nothing accounting for effects on non-target individuals? I think this would be useful to know. The model should not force the conclusion that interventions which have historically been supported by the effective altruism community (like saving human lives, and cage-free egg campaigns) are better than nothing for all reasonable moral and empirical views?

Hi Marcus. Thanks for the reply.

I wonder whether the initial testers included people with views on welfare comparisons across species similar to those that I, @NickLaing, @trammell, and @William_MacAskill have. None of us believe that animals matter exactly 0. However, we also have best guesses that the sentience-adjusted welfare range of shrimps should be much smaller than 0.1 % of that of humans. So our views would be described by an option where animal welfare matters much more than in "Only humans matter" (where animals matter exactly 0), but still significantly less than in "Animals matter, but much less than humans" (where the sentience-adjusted welfare range of shrimps is 0.1 % of that of humans).

I think adding an option with sentience-adjusted welfare ranges proportional to the individual number of neurons would let people specify their views. I suspect users would not be much bothered by having 5 options instead of 4. However, if keeping 4 options is important, I would add the option I suggested, and then have a single option replace the current intermediate options ("Animals matter, but much less than humans", and "Animals matter, but somewhat less than humans").

I understand one could use the advanced mode to specify other ways of comparing welfare across species. However, I am thinking that it is also important for the default options to cover the range of reasonable disagreement, and I believe a large part of that range for welfare comparisons across species is not covered with the current default options.

Hi Ben. Have you considered effects on soil invertebrates? I think eating eggs and chickens may impact them much more or less than chickens.

Hi Morgan. I think you are referring to this.

Scaled SADs involve an extra step, converting all pain estimates into Disabling Pain Equivalents using point estimates of scaling ratios. This is a legacy approach that we keep for information only. In April 2026, we decided to prioritize disaggregated results given our high degree of uncertainty over our pain scaling ratios, and the technical complexity involved in modeling this uncertainty.

Have you considered disaggregating the results even further by not comparing welfare across species? I agree comparisons of pains of different types (annoying, hurtful, disabling, or excruciating) within the same species are very uncertain. However, the same applies to comparisons of pains of the same type across species? I would say comparing 1 h of disabling pain in shrimps with 1 h of disabling pain in humans is much harder than comparing 1 h of disabling pain in humans with 1 h of excruciating pain in shrimps. For an intensity of a given type of pain proportional to "individual number of neuron"^"exponent", and "exponent" from 0 to 1, which covers the best guesses than I consider reasonable, 1 h of a given type of pain in shrimps is 10^-12 to 1 times as intense as 1 h of the same type of pain in humans, as shrimps have 10^-6 times as many neurons as humans. Here is some context about my uncertainty.

I would present 6 cost-effectiveness estimates:

• Days of annoying pain averted per $ (A).
• Days of hurtful pain averted per $ (B).
• Days of disabling pain averted per $ (C).
• Days of excruciating pain averted per $ (D).
• "Equivalent days of disabling pain averted per $" = "ratio between intensity of annoying and disabling pain"*A + "ratio between the intensity of hurtful and disabling pain"*B + C + "ratio between the intensity of excruciating and disabling pain"*D.
• "SADs averted per $" = "equivalent days of disabling pain averted per $"*"sentience-adjusted welfare range (as a fraction of that of humans)", where "sentience-adjusted welfare range" = "probability of sentience"*"welfare range conditional on sentience (as a fraction of that of humans)".

People could then change the pain intensity ratios, and sentience-adjusted welfare range to get their own estimates if they want. I believe presenting all the estimates above is useful because people have very different views about not only pain intensities, but also welfare comparisons across species.

At the same time, I would keep the last of the above cost-effectiveness metrics to increase transparency about trade-offs between different pain intensities and species. The trade-offs will still be made even if they are not quantified, and I worry they will be harder to examine and improve on if they are not made explicit.

@Morgan Fairless and @Vince Mak 🔸, would you find useful a time trade-off (TTO) survey asking people suffering from cluster headaches about the Welfare Footprint Institute's (WFI's) pain intensities? They may have recently experienced disabling and excruciating pain. I assume the vast majority of people who contributed to Ambitious Impact's (AIM's) estimates of the pain intensities have not recently experienced excruciating pain. So I believe such survey would provide much stronger evidence about the intensity of excruciating pain. I am asking you because AIM and Animal Charity Evaluators (ACE) are the 2 organisations using WFI's pain intensities in cost-effectiveness analyses (CEAs).

• All content from our now-closed AIM Research Training Program 

I think it is great that you have shared this.