220 karmaJoined Apr 2020


Julian Jamison is an economics professor at the University of Exeter and a Senior Research Affiliate at the Global Priorities Institute.


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Hi - thanks again for taking more time with this, but I don't think you do understand my model. It has nothing to do with capital assets, hiring/firing workers, or switching suppliers. All that it requires is that some decisions are made in bulk, i.e. at a level of granularity larger than the impact of any one individual consumer. I agree this is less likely for retail stores (possibly some of them order in units of 1? wouldn't it be nice if someone actually cared enough to look into this rather than us all arguing hypothetically...), but it will clearly happen somewhere back up the supply chain, which is all that my model requires.

Your mistake is when you write "Say they need to order in multiples of 10, and they order the minimum multiple of 10 that's at least 7 over what they predict." That's not what my model predicts (I think it's closer to M&H's first interpretation of buffers?), nor does it make economic sense, and it builds in linearity. What a profit-maximizing store will do is to balance the marginal benefit and marginal cost. Thus if they would ideally order 7 extra, but they have to order in multiples of 10 and x=4 mod10, they'll order x+6 not x+16 (small chance of one extra stock-out vs large chance of 10 wasted items). They may not always pick the multiple-of-10 closest to 7 extra, but they will balance the expected gains and losses rather than using a minimum. From there everything that I'm suggesting (namely the exponential decline in probability, which is the key point where this differs from all the others) follows.

And a quick reminder: I'm not claiming that my model is the right one or the best one, however it is literally the first one that I thought of and yet no one else in this literature seems to have considered it. Hence my conclusion that they're making far stronger claims than are possibly warranted.


I still haven't read Budolfson, so I'm not claiming that M&H misinterpret him. As I said, I did read their entire paper, and in the section specifically about him they describe two interpretations of "buffer", neither of which matches my model. So if his model is similar to mine, they got it wrong. If his model is different than mine, then they don't seem to have ever considered a model like mine. Either way a bad sign.

Everything you write about how you think they might respond to me (i.e. your three bullet points and the subsequent paragraph) is 100% consistent with my model and doesn't change any of its implications. In my model stores use predicted demand and can update it as often as they want. The point is that purchasing is in bulk (at least at some level in the supply chain); therefore there is a threshold; and the optimal threshold (every single time) will be chosen to be away from the mean prediction. This can still be extremely sensitive, and may well be. [Apologies if my brief descriptions were unclear, but please do take another look at it before responding if you don't see why all this is the case.]

To the final point, yes of course if someone decides to stop purchasing then the store [probabilistically] starts ordering fewer chickens [than otherwise]; I didn't disagree with that sentence of theirs, and it is also 100% consistent with my model. The question is the magnitude of that change and whether it is linear or not, crucial points to which they have nothing to contribute.


Yes all fair, and I'd say it goes beyond counterfactuals. I'm not sure people fully realize how sensitive many conclusions are to all sorts of assumptions, which are often implicit in standard models. I am on record disagreeing strongly with John Halstead about the likely cost-effectiveness of advocating for economic growth, and I feel similarly about much of the longtermist agenda, so this isn't specific to animals. My personal sense is that if you can save an existing human life for a few thousand dollars (for which the evidence is very clear, although point taken that the marginal impact isn't definitively pinned down - however I'd guess within a factor of two,), that's an extremely high bar to overcome.


Interesting - thanks for the extra info re Budolfson. I did in fact read all of M&H, and they give two interpretations of the buffer model, neither of which is related to my model, so that's what I was referring to. [That's also what I was referring to in my final paragraph: none of the sources you cited on that side of the causal efficacy argument seems to have considered anything like my model, which remains true given my current knowledge.]  In fact if Budolfson was saying something more like my model, which does seem to be the case, then that's an even worse sign for M&H because they must not have understood it.

The paragraph you quote from Budolfson is indeed more similar to my model, except that in my case the result follows from profit-maximizing behavior (in a competitive industry if you like!) rather than ad hoc and unusual assumptions. 

Suppose that I consider a threshold (for increasing or decreasing production next cycle) right at the mean of expected sales (15,000 in the example): half the time I'll stockout and have disappointed customers; half the time I'll have extra stock and have to sell it on a secondary market, or give it away, or waste it. Which is worse for business? Plausibly stocking out is worse. So my threshold will be higher than the mean, reducing the probability of stocking out and increasing the prob of excess. The optimal level will be set just so that at the margin, the badness of stocking out (larger) multiplied by the prob of stocking out (smaller) will exactly offset the badness of excess times the prob of excess. Because it is above the mean, which is in fact the true best-guess state of the world (ignoring any individual consumer), and because the distribution around the mean will plausibly be Gaussian (normal), which declines exponentially from the mean - not linearly! - every individual consumer should rationally believe that their decision is less than 1/n likely to be taking place at the threshold. QED.


I wasn't gesturing toward the relative competitiveness because it's important per se (you're right that it isn't) but rather as a way to gauge absolute competitiveness for those who don't already know that a net profit margin of 5.7% isn't bad at all. My intuition is that people realize that both defense and healthcare firms make decent profits (as they do) and hence that this fact would help convey that farmers (whether large or small; and if your point is that they can differentiate themselves and do some monopolistic competition then you're already on my side vs M&H) are not typically right on the edge of survival.

However I don't personally think the level of competition is crucial to anything here. M&H believe that it's necessary for their argument (in the abstract they say their case rests on it), so I was pointing out that (a) it's actually not that competitive; and (b) if they do think it's truly competitive (i.e. not differentiated) then that is indeed inconsistent with their own claim on p.23, which is a bad sign for their analysis.

My main point (which you don't seem to have responded to) remains that these are all conceptual arguments making various particular assumptions rather than actually trying to estimate an individual-level impact with a combination of a concrete well-defined model and empirics.


I had seen some of this, but not the specific paper (ungated) by McMullen & Halteman - thanks!

First of all note that the two sources you cite directly contradict one another: the first-hand anecdotal account says there is essentially no meat waste even in very small groceries, while M&H (p.12) say there is a modest constant unavoidable waste that is in fact higher in smaller / local stores than for big outfits. Indeed M&H are internally inconsistent: they say that the market is highly competitive (although they only give a very incomplete reference for this on p.14, which I couldn't find any trace of; my googling found this source suggesting a net profit margin for farming/agriculture of 5.7%, which is middling - better than aerospace/defense or healthcare), but then they also state (p.23) that larger firms have up to 60% lower costs than smaller ones -- so how do the latter survive if the industry is so competitive? All of these are bad signs right off the bat.

Second note that none of these sources actually do any data analysis or try to examine original data about the markets or supply chains; they are armchair papers. My whole point is that depending on which of several reasonable assumptions one makes, different conclusions will be drawn. The only way to adjudicate this is to actually figure out what's going on in the real world, and neither of these sources attempts to do that. Hint: neither of them gives an empirically-derived concrete estimate for individual-level elasticity.

Third (to finally answer your question!), no my hypothetical model is not the same as the way they are using the term "buffer" (which seems to be more about maintaining a minimum level of excess in the system; mine is simply about the optimal tradeoff between stockouts vs excess/waste). For instance M&H say (p.25) "if there is some probability (1/n) that any given purchase will occur on a threshold, then the threshold action will trigger a reduction in production of around n units, yielding an expected impact equal to 1" (and from the reducing suffering page: "The probability that any given chicken is the chicken that causes two cases instead of three to be purchased is 1/25"). Well yes - if it's linear then the expected effect is the same order of magnitude as the input. My model was precisely one where the probability is plausibly not linear: in any given cycle, total sales are much more likely to be near the mean than near the threshold, so every individual would correctly believe that their own actions are very unlikely to change anything, which is not inconsistent with the (obviously correct) claim that large changes in demand are roughly linear and do influence things according to whatever macro-level elasticity has been estimated for chickens.

Or my 30-second model might be wrong - I'm not claiming it's correct. I'm claiming that we don't know, and the fact that none of these sources seems to have even considered it (or any other ones), and don't even realize the nature of the assumptions they're making, and nevertheless draw such strong conclusions, is again a bad sign.


I'm a professor of economics, but thanks for the link explaining elasticity :) 

The answer is no, we can't just do that, since those approaches assume nontrivial changes (and/or they assume everything is continuous, which the real world isn't). One plausible simple model of supermarket (or restaurant) purchasing behavior is that when observed demand goes above/below a certain threshold relative to predicted demand, they buy more/less of the input next cycle. From an individual point of view, the expected aggregate demand of other agents in any time period will be a Gaussian distribution (by the law of large numbers), and the threshold will be away from the mean (doesn't make sense to update every time), which implies that one's probability of being the marginal buyer at the threshold declines exponentially (not linearly, as it would be for macro-level shifts and as you are implicitly assuming). From the ACE link: "we can approximate the supply and demand curves in this region by straight lines" - no, you can't do that (for individual behavior) without substantive additional assumptions or a lot of legwork into how these decisions actually get made.

In any case I have no idea if that's the right model, because I haven't studied supermarket supply chain management. As far as I can tell (but I'd love to see this somewhere), nobody in either the econ lit or animal welfare lit has tried to do this at the level required to make what I would consider an informed estimate; we're not just talking about a factor of 2 or 3 here. That knowledge gap doesn't seem to stop the latter group from making very strong claims; they mostly don't even seem to understand or acknowledge the high uncertainty and strong assumptions.


Thanks for the input Michael - your estimates seem reasonable / defensible to me. On the other hand, it also seems reasonable / defensible to argue that time spent just sitting around is fairly highly pleasurable for chickens (relative to their maximum): many humans prefer doing nothing to active foraging (NB I'm being serious), and chickens (like all prey) are evolved to be wary of predators and at risk of dying at any moment. My sense is that the default welfare state for all living beings is nontrivially positive (we see this in human survey data, and it makes sense evolutionarily), so a chicken that is both alive and not at risk of being eaten or starving might be in very good shape in chicken terms. I simply don't know, which leads to...

However the broader point, which all three of us seem to agree on, is that all of these estimates are wildly uncertain and should be taken with many large grains of salt and (imo) not used to draw any firm conclusions about what should happen (except that we can agree less pain is better than more pain). Reasonable people can and do disagree about what it's like to be a chicken in captivity.


Thanks again - all very constructive / helpful. I've updated some of my beliefs (partly toward the scale of this issue, as you intended, but also toward current factory farming not being as bad as I would have guessed... although I admit most people probably know less about conditions than I did), and I hope you have as well.

The only place I wanted to specifically respond is to your comment that you "sympathise with animal-welfare advocates pushing for veganism because the most common objections to it are pretty weak" - this doesn't make sense to me. We should only advocate for positions where the strongest objections are weak, not where the most common objections (which might be terrible ones) are weak. Again, tbh, it sounds more ideological than evidence- or logic-based.

I took a quick look at your linked doc and it looks good (to me): there is truly a lot of uncertainty about both basic direct outcomes (do conventional factory chickens have net positive or negative lives?) and indirect ones (what is the impact on wild animals and what is their welfare? how does it affect [human] economic and moral growth?). I would also add that while we can be sure that there is some positive elasticity between "one person stops eating chickens" to "future chicken production is lower in expectation" we don't currently have any idea what that number is (I've looked into this somewhat carefully), so that's another huge level of uncertainty. Anyone claiming that they know that the 'right' answer is not to eat animals, including many EAs and animal charities, is stepping way beyond the actual state of knowledge.


Thanks for the quick and constructive reply! 

(and yes apologies for the typo: I meant "disabling" not "debilitating")

I admit I'm still unconvinced by several of the assumptions and still believe that they require a bit more discussion / support / defense; e.g. in addition to the ones above, the claim that welfare is symmetric around the neutral point or (as discussed elsewhere in the comments) that their welfare range is 0.33 that of humans. I'm also sympathetic to the comment that was somewhat skeptical regarding the expected marginal impact of best-guess future advocacy. 

However I agree you may well be right that for a broad range of values, improving animal welfare (even if already positive, which I was too focused on) is more cost-effective than GW top charities, and this is an important point. I personally would find it even more informative and convincing to see some illustrative sets of parameter values along the lines of your "to get a ratio of 1" exercise (which I thought was a nice touch). What is the most plausible combination of values leading to a ratio of 1? However I realize it's not fair to ask you to do that - you've already put in a lot of useful work here.

As you acknowledge, an extremely broad set of parameters will lead to the conclusion that we should be eating more chickens rather than fewer. Of course the Humane League doesn't see it that way, and in general I would find animal-welfare advocates much more compelling if they didn't seem to always also push for veganism; imho it makes them sound ideological rather than evidence-driven. [You won't be surprised to hear that I'm not vegan - however I would happily vote for more humane animal farming regulations (if there were a sufficiently high probability of being pivotal...), and I'm open to being convinced to donate to charities that focus solely on improving conditions.] 

Likewise you say you yourself are open to the outcome that we should be eating more factory-farmed animals rather than fewer, which I appreciate. [although I note that in your post you refer without caveats to the "negative utility of farmed chickens"]  Given that as we've seen many plausible assumptions in your model would lead to such a conclusion, would you suggest that your framework implies that anyone believing something like those values (as I do) should in fact eat chickens and actively encourage all their friends to do so? I ask this not simply to play devil's advocate (esp since I sincerely believe in that position myself: everyone please eat more chickens!) but to continue to stress-test a bit on how seriously the model is meant to be taken with respect to any concrete conclusions.

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