Love the endeavor. But the calculation method really should be changed before anyone interested in the quantification of the combined CO2+animal suffering harm should use it, in my opinion: a weighted product model is inappropriate to express the total harm level of two independent harms, I really think you want to not multiply CO2 and animal suffering harm, but instead separately sum them, with whichever weight the user chooses. In that sense, I fully agree with what MichaelStJules also mentioned. But I want to give an example that makes this very clear—and please let me know if instead, it seems like I misread your calculation details in https://foodimpacts.org/methods :
Imagine a product A with 0 CO2 but a huge animal suffering impact, B with huge CO2 but 0 suffering, and C with non-zero but tiny impact on both dimensions. Your weighting would favor C, while for any rational person either A or B (or both) would necessarily be preferable. Your WPM may sound nicer in theory but it cannot be applied here, I’d really want to see it changed before considering the model useable for quantitative indications of the harm on a general level!
NB: I actually have an interest in using your model in the medium-term future! We’re trying to set up an animal food welfare compensation scheme, and happen to have CO2 on our list in addition to animal suffering itself, www.foodoffset.org (very much work in progress).
Imagine a product A with 0 CO2 but a huge animal suffering impact, B with huge CO2 but 0 suffering, and C with non-zero but tiny impact on both dimensions. Your weighting would favor C, while for any rational person either A or B (or both) would necessarily be preferable.
I think it’s the other way around. Under a weighted product model (WPM), the overall impact of both A and B is zero because either component is zero, so the WPM favors A and B over C. Whereas summing the climate and welfare components (with “reasonable” weights) would result in C being the most favorable.
Love the endeavor. But the calculation method really should be changed before anyone interested in the quantification of the combined CO2+animal suffering harm should use it, in my opinion: a weighted product model is inappropriate to express the total harm level of two independent harms, I really think you want to not multiply CO2 and animal suffering harm, but instead separately sum them, with whichever weight the user chooses. In that sense, I fully agree with what MichaelStJules also mentioned. But I want to give an example that makes this very clear—and please let me know if instead, it seems like I misread your calculation details in https://foodimpacts.org/methods :
Imagine a product A with 0 CO2 but a huge animal suffering impact, B with huge CO2 but 0 suffering, and C with non-zero but tiny impact on both dimensions. Your weighting would favor C, while for any rational person either A or B (or both) would necessarily be preferable. Your WPM may sound nicer in theory but it cannot be applied here, I’d really want to see it changed before considering the model useable for quantitative indications of the harm on a general level!
NB: I actually have an interest in using your model in the medium-term future! We’re trying to set up an animal food welfare compensation scheme, and happen to have CO2 on our list in addition to animal suffering itself, www.foodoffset.org (very much work in progress).
I think it’s the other way around. Under a weighted product model (WPM), the overall impact of both A and B is zero because either component is zero, so the WPM favors A and B over C. Whereas summing the climate and welfare components (with “reasonable” weights) would result in C being the most favorable.
Thank you for the feedback Florian! I will move this issue upwards in my to do list since so many of you have explained the issues with WPM.