Thanks for the update. You estimatethat excruciating pain is 48.0 (= 11.7/ā0.244) times as intense as hurtful pain. This implies 16 h of āawareness of Pain is likely to be present most of the timeā (hurtful pain) is as bad as 20.0 min (= 16ā48.0*60) of āsevere burning in large areas of the body, dismemberment, or extreme tortureā (excruciating pain). In contrast, I think practically everyone would prefer 16 h of hurtful pain over 20 min of excruciating pain.
Hey Vascoāthanks for this. As we write in the update, we are unlikely to pay much mind to scaling in the near future, in part because it has proved difficult to put numbers onto scaling in a way that satisfies us.
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 humans. For an intensity of a given type of pain proportional to āindividual number of neuronā^āexponentā, and āexponentā 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. Hereissome 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).
āEquivalent days of disabling pain averted per $ā = āratio between intensity of annoying and disabling painā*A + āratio between the intensity of hurtful and disabling painā*B + C + āratio between the intensity of excruciating and disabling painā*D.
āSADs averted per $ā = āequivalent days of disabling pain averted per $ā*āsentience-adjusted welfare range (as a fraction of that of humans)ā, where āsentience-adjusted welfare rangeā = āprobability of sentienceā*āwelfare range conditional on sentience (as a fraction of that of humans)ā.
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, @vicky_cox, and @Vince Mak šø, would you find useful a time trade-off (TTO) survey asking people suffering from cluster headaches about the Welfare Footprint Instituteās (WFIās) pain intensities? They may have recently experienced disabling and excruciating pain. I assume the vast majority of people who contributed to Ambitious Impactās (AIMās) 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 WFIās pain intensities in cost-effectiveness analyses (CEAs).
Thanks for your suggestion. I have limited capacity so apologies if I donāt answer promptly. Thanks for your suggestion on how to present CEAs, weāll think about this further.
Note: I am certainly not an animal welfare expert, and there may be very different views on this that I am not covering.
I am not sure marginal research money should be spent on pain scaling questions, I am also not bullish on most pain scaling surveys.
I prefer having stronger research on the quantification of pain in different production systems (i.e., funding welfare science that aligns to existing proposed frameworks) and exploration of other research questions.
I believe this because:
I think that existing disagregated (non scaled) metrics already allow us to make reasonable guesses for what is cost effective to help animals.
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.)
TTO surveys are super interesting and informative. As per the above Iād personally spend money on other research questions instead.
If someone were to go ahead with this. Iād be curious to try to predict what the learnings from such a survey could tangibly influence, as I expect theyād get tangled in a bunch of questions about validity anyways. Given the subjective nature of pain, I am not convinced a survey sampling from such a specific group is particularly externally valid (I also donāt know that any survey of humans will ever be externally valid to how weād scale pain across other animals).
Thanks for your suggestion on how to present CEAs, weāll 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. āThe analysis primarily aimed to estimate the minimum welfare improvement associated with transitioning to cage-free housingā. 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 donāt know that any survey of humans will ever be externally valid to how weād scale pain across other animals).
I agree comparisons across different pain intensities and species will remain very uncertain.
People could then change the pain intensity ratios, and sentience-adjusted welfare range to get their own estimates if they want.
Here is a comment from Bob Fischer with context about the uncertainty in the sentience-adjusted welfare ranges Rethink Priorities (RP) initially presented, and the similar ones in Bobās related book which I understand inform your own estimates a lot.
Thanks for the update. You estimate that excruciating pain is 48.0 (= 11.7/ā0.244) times as intense as hurtful pain. This implies 16 h of āawareness of Pain is likely to be present most of the timeā (hurtful pain) is as bad as 20.0 min (= 16ā48.0*60) of āsevere burning in large areas of the body, dismemberment, or extreme tortureā (excruciating pain). In contrast, I think practically everyone would prefer 16 h of hurtful pain over 20 min of excruciating pain.
Hey Vascoāthanks for this. As we write in the update, we are unlikely to pay much mind to scaling in the near future, in part because it has proved difficult to put numbers onto scaling in a way that satisfies us.
Hi Morgan. I think you are referring to this.
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 humans. For an intensity of a given type of pain proportional to āindividual number of neuronā^āexponentā, and āexponentā 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).
āEquivalent days of disabling pain averted per $ā = āratio between intensity of annoying and disabling painā*A + āratio between the intensity of hurtful and disabling painā*B + C + āratio between the intensity of excruciating and disabling painā*D.
āSADs averted per $ā = āequivalent days of disabling pain averted per $ā*āsentience-adjusted welfare range (as a fraction of that of humans)ā, where āsentience-adjusted welfare rangeā = āprobability of sentienceā*āwelfare range conditional on sentience (as a fraction of that of humans)ā.
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, @vicky_cox, and @Vince Mak šø, would you find useful a time trade-off (TTO) survey asking people suffering from cluster headaches about the Welfare Footprint Instituteās (WFIās) pain intensities? They may have recently experienced disabling and excruciating pain. I assume the vast majority of people who contributed to Ambitious Impactās (AIMās) 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 WFIās pain intensities in cost-effectiveness analyses (CEAs).
Hi Vasco,
Thanks for your suggestion. I have limited capacity so apologies if I donāt answer promptly. Thanks for your suggestion on how to present CEAs, weāll think about this further.
Note: I am certainly not an animal welfare expert, and there may be very different views on this that I am not covering.
I am not sure marginal research money should be spent on pain scaling questions, I am also not bullish on most pain scaling surveys.
I prefer having stronger research on the quantification of pain in different production systems (i.e., funding welfare science that aligns to existing proposed frameworks) and exploration of other research questions.
I believe this because:
I think that existing disagregated (non scaled) metrics already allow us to make reasonable guesses for what is cost effective to help animals.
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.)
TTO surveys are super interesting and informative. As per the above Iād personally spend money on other research questions instead.
If someone were to go ahead with this. Iād be curious to try to predict what the learnings from such a survey could tangibly influence, as I expect theyād get tangled in a bunch of questions about validity anyways. Given the subjective nature of pain, I am not convinced a survey sampling from such a specific group is particularly externally valid (I also donāt know that any survey of humans will ever be externally valid to how weād scale pain across other animals).
Thanks for sharing your thoughts.
Great.
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. āThe analysis primarily aimed to estimate the minimum welfare improvement associated with transitioning to cage-free housingā. 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 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.
I agree comparisons across different pain intensities and species will remain very uncertain.
Here is a comment from Bob Fischer with context about the uncertainty in the sentience-adjusted welfare ranges Rethink Priorities (RP) initially presented, and the similar ones in Bobās related book which I understand inform your own estimates a lot.