But what if it were chicken?A key part undermining the cost-effectiveness is that each pig produces so much pork. If we re-run the numbers assuming that the study was talking about chicken instead of pork and had the same results, but adjusted all the other numbers to be about chicken, we get $5.70 per chicken spared (90% interval: $0.71 to $32) and $50 per chicken year (90% interval: 6.3 to 280). This is better, but presumably still not as good as helping humans (even from a complete species-neutral point of view). This is summarized in this additional Guesstimate model.

It appears that your model for chickens assumes that the amount of chicken eaten each time is the same as the amount of pork eaten each time and that the reduction in the number of times per month that chicken would be eaten is the same as the reduction in the number of times per month that pork was eaten. One potential problem with this assumption is that people each more chicken than pork: according to USDA statistics, in 2015, people ate, on average, 51.1 pounds of chicken but 'only' 31.4 pounds of pork. For your model to be accurate, it would have to be the case that showing videos of animal mistreatment reduces the amount eaten by a similar magnitude across different products regardless of the baseline amount eaten. It seems more likely to me that videos would reduce amount eaten by a similar proportion such that the reduction would be greater for products with a higher baseline amount eaten. If this is correct, then the reduction in the amount of chicken eaten would be 1.627 times what you estimated [51.1 pounds / 31.4 pounds].^^ This means that the cost per chicken spared and the cost per chicken year spared should be multiplied by 0.615 [1 / 1.627] to account for people reducing their consumption of chicken more (in absolute terms).

^^You might think the ratio should be set higher if you think that the Animal Equality audience has a higher than average chicken consumed to pork consumed ratio.

We also have to account for the model using the carcass weight of chickens^^^ as the number of fewer pounds people have to eat to spare one chicken. As noted above (with respect to pigs), this approach seems wrong in that each fewer pound of chicken eaten likely results in more than one fewer pound of chicken carcass being produced. According to USDA statistics, in 2015, 103.9 pounds of chicken carcass were produced per person while only 51.1 pounds of chicken were eaten per person, meaning that 2.033 pounds of chicken carcass were produced per pound of chicken eaten [103.9 pounds / 51.1 pounds]. Assuming that one fewer pound of chicken being eaten resulted in 2.033 fewer pounds of chicken carcass being produced, the cost of sparing one chicken and the cost of sparing one chicken year need to be multiplied by 0.492 [1 / 2.033].

^^^I assume that "Amount of meat per chicken (lbs)" in your model refers to carcass weight as it does in the pig model. I make this assumption for two reasons. First, the phrase you used in the chicken model is similar to what you used in the pig model ("Amount of meat per pig (lbs)"), where that phrase refers to carcass weight. Second, the source you use for the pig model says that chickens have a mass of 2.5 kilograms and that their carcass after slaughter retains 75% of that mass, meaning that a chicken carcass is around 1.875 kilograms (4.134 pounds); 4.134 pounds is roughly the midpoint of your range of 3 pounds to 5 pounds, which makes me think that your number was based on the carcass number from that source.

Thus, to account for videos reducing chicken consumption by more than they reduce pork consumption (due to people eating more chicken) and to account for each fewer pound of chicken being eaten resulting in more than one fewer pound of chicken carcass being produced, your estimates should be multiplied by 0.303 [0.615 * 0.492]. This results in the cost of sparing a chicken being $1.73 [0.303 * $5.70] with a 90% interval from $0.22 [0.303 * $0.71] to $9.70 [0.303 * $32] and the cost of sparing a chicken year being $15.15 [0.303 * $50] with a 90% interval from $1.91 [0.303 * $6.30] to $84.84 [0.303 * $280].

You might also think that showing people a video about the treatment of chickens would reduce the amount of turkey eaten by the same proportion as it reduces the amount of chicken eaten. According to USDA statistics, Americans ate, on average, 7.9 pounds of turkey, which is 0.155 times how much chicken they ate [7.9 pounds / 51.1 pounds]. If only 0.155 times as many pounds of turkey are being saved per viewer, then you would have to show the video to 6.452 times as many viewers to save the same number of pounds of turkey [1 / 0.155].

Additionally, since turkey carcasses weigh 23.603 pounds (0.75 * 31.47 pounds) (compared to 3.9 pounds for chickens^^^^), you would have to show the video to 6.052 times as many viewers to spare the same number of turkeys [23.603 pounds / 3.9 pounds].^^^^^ This means that it costs 39.048 times as much to spare a turkey [6.452 * 6.052], which means that the cost of sparing one turkey is $67.55 [39.048 * $1.73] with a 90% interval from $8.59 [39.048 * $0.22] to $378.77 [39.048 * $9.70].^^^^^^

^^^^I use 3.9 pounds because that is what is used in the Guesstimate model for chickens and I am deriving the estimates for turkeys from the estimates for chickens.

^^^^^The percent of turkey carcass that is ultimately eaten (49.6%) is similar to the percent of chicken carcass that is ultimately eaten (49.1%).

^^^^^^I am assuming that the cumulative elasticity factor for turkey is similar to the cumulative elasticity factor for chicken. The Animal Charity Evaluators spreadsheet you cite reports similar estimated cumulative elasticity factors for chicken and turkey.

And since turkeys live around four months on factory farms, the cost of sparing one turkey year is $202.65 [3 * $67.55] with a 90% interval from $25.77 [3 * $8.59] to $1,136.31 [3 * $378.77].

Combining the chicken and turkey numbers, we get that the cost of sparing one bird is $1.69 [1 / (1 / $1.73 + 1 / $67.55)] with a 90% interval from $0.21 [1 / (1 / $0.22 + 1 / $8.59)] to $9.46 [1 / (1 / $9.70 + 1 / $378.77)] and the cost of sparing one bird year is $14.10 [1 / (1 / $15.15 + 1 / $202.65)] with a 90% interval from $1.78 [1 / (1 / $1.91 + 1 / $25.77)] to $78.77 [1 / (1 / $84.64 + 1 / $1,136.31)].

Finally, if you accept Halstead's argument that assuming persistence of 1 to 12 years is too optimistic (with a point estimate of 68 months) and that a more reasonable point estimate would be 6 months, then you would think that it costs 11.333 times the above estimates to spare an animal and to spare an animal year [68 / 6]. This would result in the cost of sparing a pig being $841.48 [11.333 * $74.25] with a 90% interval from $129.08 [11.333 * $11.39] to $3,141.51 [11.333 * $277.20] and the cost of sparing one pig year being $1,739.05 [11.333 * $153.45] with a 90% interval from $263.72 [11.333 * $23.27] to $6,170.82 [11.333 * $544.50]. It would also result in the cost of sparing a chicken being $19.61 [11.333 * $1.73] with a 90% interval from $2.49 [11.333 * $0.22] to $109.93 [11.333 * $9.70] and the cost of sparing a chicken year being $171.69 [11.333 * $15.15] with a 90% interval from $21.65 [11.333 * $1.91] to $961.49 [11.333 * $84.84]. It would additionally result in the cost of sparing a turkey being $765.54 [11.333 * $67.55] with a 90% interval from $97.35 [11.333 * $8.59] to $4,292.60 [11.333 * $378.77] and the cost of sparing a turkey year being $2,296.63 [11.333 * $202.65] with a 90% interval from $292.05 [11.333 * $25.77] to $12,877.80 [11.333 * $1,136.31]. Lastly, it would result in the cost of sparing a bird being $19.15 [11.333 * $1.69] with a 90% interval from $2.38 [11.333 * $0.21] to $107.21 [11.333 * $9.46] and the cost of sparing a bird year being $159.80 [11.333 * $14.10] with a 90% interval from $20.17 [11.333 * $1.78] to $892.70 [11.333 * $78.77].

[Throughout this comment and the parent comment, I've adjusted point estimates and 90% intervals simply by multiplying them by the adjustment factor. I'm unsure whether this approach is correct for 90% intervals.]

*2 points [-]