I do not think that they are "making it up"; that phrase to me seems to attach all sorts of deliberate malfeasance that I do not wish to suggest. I think that to an outside observer the estimate is optimistic to the point of being incredible, and reflecting poorly on CEA for that.

These 291 people haven't pledged dollar values. They've pledged percentage incomes. To turn that into a dollar value you need to estimate whole-life incomes. Reverse engineering an estimate of income (assuming that most people pledge 10%, and a linear drop off in pledgers with 50% donating for 40 years), yields mean lifetime earnings of ~£100K. That's about the 98th centile for earnings in the UK.

Hi Will,

I'm glad to hear that a general response is being collated; if there are things where CEA can improve it would seem like a good idea to do them, and if I'm wrong I would like to know that. Turning to the listed points:

• I went into that conversation with a number of questions I sought answers to, and either asked them or saw the data coming up from other questions. I knew your time was valuable and mostly targeted at other people there.

• Adam explicitly signed off on my comment to Luke. He saw the draft post, commented on it, recommended it be put here and received the original string of emails in the context of being a friend, and person I knew would have a closer perspective on the day to day running of CEA than myself.

• £1700 came from Jacob (Trefethen), in conversation shortly after you were in Cambridge, and purporting to be from internal numbers. I had asked whether CEA has an internal price at which new pledges would be bought, on the basis that one should exist, and it would be important for valuing a full-time Cambridge position.

• ~4K is 1/3 of the Oxford undergrad population, which was the figure I had heard quoted in the discussion in Cambridge.

• GWWC lists 8 people as a sample of past-and-present researchers, a research manager and a research director. I estimated that half of the former set would have moved on, and thus that 6 people were at least engaged in part time research for GWWC.

I am concerned both about utility-maximisation and the ROI. It seems easier to fix efficiency problems whilst institutions are still small, or create alternate more efficient institutions if need be; ideally groups akin to CEA's projects are going to move budgets of O(10^9 / year), and I want to see that used as effectively as possible.

In terms of ROI, I don't put large weight in the estimated returns absent a calculation or substantial trust in the instrumental rationality of the organisation making the claims. To take the canonical example, GiveWell provides some measure of each; CEA's projects need to be at least as credible.

Thanks again for taking the critique in the spirit that was intended.

Best wishes,

Jonathan

The primary source of the post was an extensive email exchange with Adam Casey (currently working full time at CEA). Since we are friends, this was not primarily in an official capacity. I also asked Adam to cross check the numbers whilst wearing a more official hat.

I was encouraged by him and Alexey Morgunov (Cambridge LWer) to make the substance of this public immediately after Will Crouch came up to Cambridge.

Whose status ordering are you using? Getting someone who is not a mathematician to TMS is harder; within the Natural Sciences it is possible, and there are O(1) Computer Scientists, philosophers or others. For the historians, classicists or other subjects, mathmos are not high status. In terms of EtG, these groups are valuable - most traders are not quants.

In that case, having a claim on every page of the GWWC site claiming that £112.8M have been pledged seems deceptive. 291 people have pledged, and [by a black box that doesn't trivially correspond to reality] that's become £112.8M. I know that at least 3 people in Cambridge have seen that statistic and promptly laughed at GWWC. The numbers are implausible enough that <5s Fermi estimates seem to refute it, and then the status of GWWC as somewhat effective rational meta-charity is destroyed. Why would someone trust GWWC's assessment of charities or likely impact over, say, GiveWell, if the numbers GWWC display are so weird and lacking in justification?

Talking about effective altruism is a constraint, as is talking about mathematics. Being a subject society makes it easier to get people from that subject to attend; it also makes it harder to convince people from outside that subject to even consider coming.

TMS pulls 80+ people to most of its talks, which are not generally from especially famous mathematicians. TCSS got 600 people for a Pensrose-Rees event. Both TCSS and TMS have grown rapidly in 18-24 months, having existed for far longer. This seems to indicate that randomly selected student societies have low hanging fruit. It doesn't seem incongruous to suggest that OUIS, OUSS and GWWC have the capacity to at least double their attendances -- the TMS did in one term, and doubled the number of events (so a x4 in person-talks).

This holds for graduates who earn less than average as well. Is there data showing that the predominant source of career changes are people who would otherwise earn substantially less than mean? Is there data suggesting that the career changes are increasing incomes substantially?

We might mean many things by "2 + 2 = 4". In PA: "PA |- SS0 + SS0 = SSSS0", and so by soundness "PA |= SS0 + SS0 = SSSS0" In that sense, it is a logical truism independent of people counting apples. Of course, this is clearly not what most people mean by "2+2=4", if for no other reason than people did number theory before Peano.

When applied to apples, "2 + 2 = 4" probably is meant as: "apples + the world |= 2 apples + 2 apples = 4 apples". the truth of which depends on the nature of "the world". It seems to be a correct statement about apples. Technically I have not checked this property of apples recently, but when I consider placing 2 apples on a table, and then 2 more, I think I can remove 4 apples and have none left. It seems that if I require 4 apples, it suffices to find 2 and then 2 more. This is also true of envelopes, paperclips, M&M's and other objects I use. So I generalise a law like behaviour of the world that "2 things + 2 things makes 4 things, for ordinary sorts of things (eg. apples)".

At some level, this is part of why I care about things that PA entails, rather than an arbitrary symbol game; it seems that PA is a logical structure that extracts lawlike behaviour of the world. If I assumed a different system, I might get "2+2=5", but then I don't think the system would correspond to the behaviours of apples and M&M's that I want to generalise.

(On the other hand, PA clearly isn't enough; it seems to me that strengthened finite Ramsey is true, but PA doesn't show it. But then we get into ZFC / second order arithmetic, and then systems at least as strong as PA_ordinal, and still lose because there are no infinite descending chains in the ordinals)

Thanks. Definite typo, Fixed.