For considering flow-through effects, I would want to distinguish between dimensions like the following:

• Improves someone's life quality
• Improves values
• Increases economic growth
• Differential technological progress
• Improves institutions

I ordered these in ascending order of importance with how likely I think they're going to have a big impact. I think all of those look more likely positive than negative to me, except for economic growth where I have no idea (though I note that more people lean in the direction of it being positive, and considering it negative is maybe a bit of a brittle argument) .

Probably a lot of people would put "improves values" above economic growth in terms of relevance on the future, but my intuitions go in the direction of technological determinism and the view that if things go poorly, it's more because of hypocrisy and lack of competence rather than "bad values."

To get back to your question: I think I'd approach this by looking for correlations between what you call "good things" and the other factors on my list. I'd say there's a significant positive correlation. So I'd say "good things have good flow-through effects" because of that positive correlation. If you find an example where you improve someone's life quality but it doesn't have any effect on the other variables, I wouldn't expect positive flow-through effects from that.

I'm broadly in your camp, i.e. starting with a 50-50 prior.

I think a useful intuition pump is asking oneself whether some candidate good near-term effect/action X is net good for total insect welfare or total nematode welfare over the next 0-5 years (assuming these are a thing, i.e. that insects or nematodes are sentient). I actually suspect the correlation here is even smaller than for the short-term vs long-term impact variables we typically consider, but I think it can be a good intuition pump because it's so tangible.

I agree with "first-order effects are usually bigger than second-order effects", but my model here is roughly that we have heavy-tailed uncertainty over 'leverage', i.e. which variable matters how much for the long-term future (and that usually includes sign uncertainty). 

We can imagine some literal levers that are connected to each other through some absurdly complicated Rube Goldberg machine such that we can't trace the effect that pulling on one lever is going to have on other levers. Then I think our epistemic position is roughly like "from a bunch of experience with pulling levers we know that it's a reasonable prior that if we pull on one of these levers the force exerted on all the other levers is much smaller, though sometimes there are weird exceptions; unfortunately we don't really know what the levers are doing, i.e. for all we know even a miniscule force exerted – or failing to exert a miniscule force – on one of the levers destroys the world".

Hmm, my mind doesn't have a single bucket for "good things within the next few years". When I think about it I immidiately unpack it to things like:

• increase the influence, competence and wisdom of altruistic groups and individuals – >>50% (off the cuff)
• decrease the risk of global catastrophes in the near term – >>50%
• improve the standard of living, wealth, health, ... – >50%
• increase economic growth – >50%

I would imagine a sensible model has goodness persisting in expectation but asymptotically approaching 0. That seems both reasonably intuitive and to lead to some helpful guidance once you have such a model.

The question of what the relative decay rate for different classes of action is then becomes paramount - if you can identify actions with low expected decay rates, you have a phenomenally important class of actions. Extinction events are perhaps the example in which we can have highest confidence in a low decay rate, but highest confidence in a low decay rate doesn't necessarily = highest expected decay rate (this is maybe another way of thinking about trajectory change).

I think it's >60% likely that if an intervention doesn't contribute significantly accelerating the development of technology which could pose existential risks, and is highly likely to be net positive for the experience of sentient beings in the next 0-5 years, then it has a net positive effect on the long-term future. I have no idea whether a completely undefined "arbitrarily chosen" intervention that is net positive for the next 0–5 years is likely to contribute to risky technology, since I feel confused about what would be a reasonable sample of five such arbitrarily chosen interventions. I might have a 50–50 prior just because of that fact, but that doesn't seem like a good reason to have a 50–50 prior.

I agree with you that 'good now' gives us in general no reason to think it increases P(Utopia), and I'm hoping someone who disagrees with you replies.

As a possible example, that may or may not have reduced P(Utopia), I have a pet theory, that may be totally wrong, that the Black Death, by making capital far more valuable in Europe for a century and a half was an important part of triggering the shifts that caused Europe to be clearly ahead of the rest fo the world in the tech tree leading to industrialization by 1500 (claiming that Europe was clearly ahead by 1500 is also a disputed claim).

Assuming we think an earlier industrialization is a bigger good thing than the badness of the black death, then the black death was a good thing under this model.

Which line of thinking is how I learned to be highly skeptical of 'good now' = 'good in the distant future'.