We all know that an extra dollar is worth more to you the poorer you are. That's why it can be good to donate money to an organisation like GiveDirectly even when a few cents in the dollar get used up in transaction costs. But how much more is it worth? Economists have a good quantitative model of what is going on, which can enable us to make rough comparisons about whether, say, people on $1,000 per year would get more value from an extra $100 than people on $2,000 per year would get from $200. This can help us work out how much additional cost we should bear to get money to the very poorest people.
It can also be useful for improving our thinking about the relative values of different financial flows such as remittances and aid. It is easy to find out the sizes of these in dollars, but what about the size in terms of value to the individuals? If the individuals in one case are substantially richer, then this can really change things.
I've written an article explaining how all of this works up on centerforeffectivealtruism.org. Have a read and let me know what you think.
I like the article. The first table makes it viscerally available that the VOI for better estimating eta (or for finding a better model for utility as a function of consumption on the margins) could be high, if you're relatively more interested in global poverty-focused EA than in other causes within EA.
I'm not aware of any better figures you could have used for GWWC/TLYCS/REG's leverage, and I'm not sure if many of us take estimates of leverage for meta-organizations literally, even relative to how literally we take normal EA cost-effectiveness estimates. I agree that combining the leverage estimates with the consumption multipliers in order to estimate impact would be the correct thing to do if you managed to get accurate estimates of both that weren't dependent or interdependent on each other, though!
To the extent that GWWC/TLYCS/REG count donations that they have received themselves as having a certain leverage because of the donations "caused"/influenced by GWWC/TLYCS/REG, everyone who has had their donations "caused"/influenced by GWWC/TLYCS/REG (at least according to GWWC/TLYCS/REG) should count their donations as having proportionally less than 1.0x leverage. (Alternatively, GWWC/TLYCS/REG could claim to have less leverage, and thereby allow those who they claim to have influenced to claim that they've caused a greater fraction of the impact that their own donations have caused). This prevents double-counting of impact, and gives us a more accurate estimate of how much good donations to various organizations cause, which in turn lets us figure out how we can do the most good.