my example was merely trying to show that if patient philanthropy is preferred, then a wait and donate strategy is better than relying on inter-generational transfers.

we have to assume that for some arbitrary reason we do not care about the first three generations of poor people at all, only about the poor people in 100 years' time

No, we don't. We merely have to believe (in expectation) that our marginal money is better spent a few generations in the future than on the current generation. This is of course contested but there are plenty of non-arbitrary reasons to believe it. For example, if you doubt catch-up growth, and you think there will still be some very poor (in absolute terms) countries around a few generations in the future, then a few generations the future you will expect to have

• more money, due to compound returns of your savings
• a population of people that are about as easy to help as they are now

So you can help people more then than you can now. (this is obviously glossing over a ton of details like those covered in Trammel's report but I think it helps get at the intuition).

Most individual-level income gains like we see from tin roofs do not compound across generations at anything like market rates (we can see inter-generational income elasticity is far less than 1 in low-income countries which implies income gains to one generation get diluted over time).

So lets say we are targeting population P - these are the recipients. P is the population of people most in need that will be around in 100 years. Most of them do not currently exist. We want to spend money to help P either in the form of direct cash transfers or health interventions.

We can do that by investing our money and then handing it out to the individuals in P once they come into existence. This is option A, aka the patient philanthropy strategy.

We could also give to the parents or grandparents of P, some of which are alive today, which we can call P_p and P_g. I am assuming this is what you mean by "Give it to their ancestors.". I call this Option B. Option B is worse because:

•  some of the money is consumed by P_p and P_g instead of passed thru to P. In this example we are assuming P is where our money is the most cost-effective so this is bad.
• since we don't know what areas will be most in need for the next few generations we don't know quite who P_p and P_g are.

see my previous comment:

• Option A: Put money in an index fund, let it grow, spend it in 100 years
• Option B: give it to people who will spend some of it now, invest some, pass on some to their children, who will in turn spend some of it, invest some of it, and pass it onto their children, leaving some for their grandchildren to spend in 100 years.

Option A leads to a bigger counterfactual increase in spending-100-years-from-now which is what we care about in this (admittedly contrived) example

Giving it to their ancestors is choosing option B

Well in this case the recipients do not currently exist so I cannot yet give them any money. 

Not necessarily. Let’s say a patient philanthropy foundation wants to expropriate, say, half of the inherited wealth between this generation and the next (in order to invest it for a future generation). The current generation would rationally prefer this not to happen. Conversely, the current generation would prefer to receive from the foundation an amount of wealth equivalent to half the wealth the next generation will be able to inherit.

The fundamental point is that investing wealth to accumulate wealth might make your impact numbers go up, because of an arbitrarily accounting decision, but it doesn’t make the well-being of the people you’re trying to help go up, as measured by their rational preferences or revealed preferences.

I'm not sure I understand this line of argument. Let's say the world is such that spending in 100 years (i.e on people who do not currently exist and cannot actualize their preferences) is especially cost-effective or otherwise useful. There are two ways of "putting money 100 years into the future".

• Option A: Put money in an index fund, let it grow, spend it in 100 years
• Option B: give it to people who will spend some of it now, invest some, pass on some to their children, who will in turn spend some of it, invest some of it, and pass it onto their children, leaving some for their grandchildren to spend in 100 years.

Option A leads to a bigger counterfactual increase in spending-100-years-from-now which is what we care about in this (admittedly contrived) example. 

I agree setting up 100-year foundations is hard; but there are more practical steps one can take if they are convinced of the general arguments for patient philanthropy, most simply giving later in their lives or in their wills (I'm not necessarily endorsing this, but I think it is worth considering).

The rational preference argument only applies for giving to the current generation of recipients at some later point in their lives. If the most cost effective generation to help is really, say, 3 generations in the future we should save and then give to them instead.

The cost-effectiveness argument is more convincing but the case for patient philanthropy only requires there to be some large-enough region that stagnates growth-wise which unfortunately seems likely given the perennial nature of bad governance.  I believe that if you make some simplifying assumptions about utility functions and population size, patience looks good iff the projected rate of return on your assets is greater than the projected income growth rate for your target population.

I agree donating now to promote economic growth in poor countries is likely preferable to delaying donations by 100 years, though I am unsure about the tractability of any particular growth intervention.

I also found their neglect to mention to mention smokeless products strange. In Norway and Sweden, for example, snus has been replacing cigarettes.

There are not too many case studies to look at here, but in Bhutan, their 2010 ban on the importation and sale of all tobacco products (which was coupled with government counseling and treatment to facilitate cessation) proved controversial and difficult to enforce in the face of large-scale smuggling and was eventually scaled back in 2021. 

fair points! I should have been explicit here but I was invoking epistemological humility primarily in response to SMA's public statements about the tobacco industry which in my view do not seriously engage with the idea that tobacco use could be a free-but-harmful or free-and-beneficial choice for any consumers.

I would push back on the idea that the harm/benefit ratio to smoking is somehow 'medically settled'. The fact that cigarettes greatly increase risk of lung cancer, say, is settled but for the harm/benefit ratio to be settled it would require us to be able to put the harm and benefit in comparable units; the correct procedure for which is, in my view, a epistemological mystery (the problem here seems similar to trying to get an unambiguous answer with health economics whether to go on a fun-but-risky rafting trip or a safe-but-boring trip to the mall).

I do believe the freedom to choose self-destructive habits is an important principle worth defending though I don't think that claim is necessary for the more narrow point I was making in this post.

In what way do you find it unrepresentative? Just curious because I am unfamiliar with the dynamics here.