No, I don’t think this is the right way to model this. This looks a lot like the typical error people make for the original two envelopes problem.

1. Initial welfare (what does that mean?) and final welfare after inaction can differ, because the world, e.g. land use, will change even if you do nothing, and campaigns take time for their effects to materialize.
2. If you swapped the roles of campaign and inaction, you would flip the conclusion, too.

It was illustrative.

Inaction also does not in fact lead to welfare of 0 with probability 100%. There will be lots of animals suffering and many possible outcomes if we do nothing. So it's not correct to assume total welfare of 0.

If you instead set the campaign option to 0 welfare and defined the welfare of the world with inaction relative to the campaign option, you'd end up with the opposite conclusion, that only inaction reaches -1.

Avoiding the worst is meant to treat each option symmetrically. It doesn’t depend (in theory) on which option you single out to define things relative to.

(RP's practical procedure does start with inaction, but if you end up with the same probability distributions for each option in the end, the results will be the same as if you started with a different option to define all distributions relative to. I think their procedure helps ensure consistent probability assignments and is less work, compared to directly estimating each distribution independently.)

Imagine the world has welfare 0.

With inaction, the final welfare will be 0 with probability 100 %.

This is exactly a procedure you could follow for difference-making risk aversion; it's equivalent to taking the statewise difference with inaction. The welfare of the world with inaction isn't 0 with probability 100%.

RP has a model/procedure for avoiding the worst risk aversion here.

Ah, sorry, I was too quick and should have read more carefully.

However, I believe the distribution with the campaigns has longer positive and negative tails

Why do you believe this?

As chicken and egg prices increase from these welfare reforms, I would expect:

1. some shifts between crops and nature (including through substitution), but I'm clueless about which involves more suffering, so this doesn't clearly favour one or the other.
2. substitution towards beef and other pasture products, which reduces invertebrate populations substantially, and probably without making lives much worse. This would mean less suffering and so do better in the worst case.

I agree. So the worst case is that the campaigns cause lots of suffering (relative to inaction)?

I don't think this is right. I think you're still treating "Avoiding the worst" like a difference-making view. You shouldn't be thinking in terms of "relative to inaction", which itself has a highly uncertain distribution of outcomes. Just evaluate the distribution of outcomes for each option, without fixing any as a comparison option.

The question is only whether worst-case outcomes are more or less likely with action or inaction.

FWIW, the actual worst cases are s-risks, and I'd expect "Avoiding the worst" views to prioritize their mitigation, as long as we're not clueless about that.

Interventions which cost-effectively increase the welfare of vertebrates will change land use much more than inaction, and a greater change in land use increases the probability of causing lots of suffering?

It might cause lots of suffering, but it could also prevent lots of suffering, too. I think you're thinking in terms of difference-making, but "Avoiding the worst" risk aversion is not difference-making. Rather than thinking about what you cause, you should just look at both (distributions of) outcomes and ask which has more suffering in it, without privileging the results of inaction. 

Unless you believe the expected amount of wild animal suffering is higher all-things-considered than with inaction, you shouldn't really expect it to do worse according to "Avoiding the worst" risk aversion (as a heuristic; there could be exceptions).

I don't think welfare interventions targeting vertebrates will necessarily look worse than doing nothing on "Avoiding the worst" views, because they don't specifically, AFAIK, increase the risks of worse cases than inaction. I think things that reduce land use for agriculture, including a lot of alt protein and veg advocacy work, plausibly do look bad in the near-term on "Avoiding the worst" views, because the near-term worst cases are where invertebrates have bad lives, modest/high moral weights and larger populations.

But I do think on many difference-making views that compare to some default option like inaction and weigh downsides at least linearly and more than upsides, most interventions will look worse than the default.

I also have a similar comment here and a piece critiquing and exploring different versions of difference-making more generally here. A version of difference-making that wouldn't let invertebrates dominate would be one that discounts both more extreme upsides and more extreme downsides (especially symmetrically) relative to a comparison option (more).

I agree with Craig here. I've written about problems with most conceptions of utility people use and describe alternatives that I think better match what Craig is saying in this sequence.

Hmm, the view in my sequence Radical empathy is consequentialist-compatible and judgemental, but is designed to judge exactly as others judge, on their behalf.