Beating the market consistently is hard to impossible because the market is unpredictable. But the collective mood swings (animal spirits?) behind its ups and downs are anything but rational.

And yes, there may be arbitrage opportunities in poverty alleviation. Microfinance was an "above market" investment until the market assimilated that loan payment rates were better than the previous consensus estimates.

I would talk about "correlations" more than "tradeoffs." Reducing pollution, for example, will likely lead to lives that are both longer and happier.

I read somewhere that a big failure of the movement to reduce climate carbon emissions is its focus on climate change (which is a contentious issue despite the mass of evidence). However, reducing carbon emissions will also reduce air pollution, which kills thousands upon thousands even in the developed world. The benefits of lowering pollution are obvious, non-contentious, and don't depend on climate models that most people do not understand. So why not campaign for clean air, and get global warming reduction as a collateral benefit?

You assume that "egotistically motivated people" are rational actors; they are not. Homo economicus is a myth.

I have spent over two decades in the private sector, and I can attest that biases, bad information, warped incentives, and herd mentality run rampant (if you don't believe me, look at the behavior of the stock market).

You ask: why aren't banks lending money for people to pay to get themselves dewormed? Possible answers include:

• Bankers expect do-gooders to overstate their case (likely true, but probably not more than for businessmen and other borrowers)
• Bravado - bankers want to look "hard-nosed" in front of their peers; charities look "weak"
• Laziness - ROI for poverty alleviation may be more difficult to estimate (or NGO workers may be worse at presenting a business case)
• Fear - if the project fails, it will be harder to explain to the boss than your standard bankruptcy
• Status seeking - better to be seen around "captains of industry" than low-status do-gooders (or even lower-status peasants)
• Prejudice/bigotry - what if the beneficiaries of deworming are of a different race/religion than the bankers?
• Ignorant and arbitrary bank goals and policies

In many cases, there is no consensus on what is morally excellent. Some parents believe it is morally excellent to subject their daughters to a cliterectomy; I beg to disagree. My workmate J. believes that hunting is morally neutral; my kids find it abhorrent.

Or there may be a disconnect between what you affirm to be morally excellent and what you feel to be morally excellent. I have a rough idea of how many lives I could save by depriving my kids of a college education and donating the proceeds to GiveWell, and yet I won't do it (and would feel guilty if I did).