Evaluation of the top charity is incredibly inaccurate (low probability of correctness), and taking that into account the difference in expected payoff between the good charities should be quite small. Meanwhile if there exist a population sharing a flaw in the charity evaluation method (the flaw that you have), the payoff for finding a method of exploitation of this particular flaw is inversely proportional to how much they diversify.
Doesn’t follow. If you have a bunch of charities where the difference in expected payoff is the same, donating any one of them has the same expected value as splitting your donation among all of them. If you have a charity with a even slightly higher expected payoff, you should donate all of your money to that one, since the expected value will be higher.
E.g.: Say that Charity A, Charity B...Charity J can create 10 utilons per dollar. Ergo, if you have $100, donating $100 to any of the ten charities will have an expected value of 1000 utilons. Donating $10 to each charity will also have an expected value of 1000 utilons. Now suppose Charity K comes on to the scene, with an expected payoff of 12 utilons per dollar. Donating your $100 to Charity K is the optimal choice, as the expected value is 1200 utilons.
Doesn’t follow. If you have a bunch of charities where the difference in expected payoff is the same, donating any one of them has the same expected value as splitting your donation among all of them. If you have a charity with a even slightly higher expected payoff, you should donate all of your money to that one, since the expected value will be higher.
E.g.: Say that Charity A, Charity B...Charity J can create 10 utilons per dollar. Ergo, if you have $100, donating $100 to any of the ten charities will have an expected value of 1000 utilons. Donating $10 to each charity will also have an expected value of 1000 utilons. Now suppose Charity K comes on to the scene, with an expected payoff of 12 utilons per dollar. Donating your $100 to Charity K is the optimal choice, as the expected value is 1200 utilons.