You can look at GiveWell's analysis, or look at the work done by GiveDirectly and Watsi. One of the challenges with charity, though, is that you don't just wan

You can look at GiveWell's analysis, or look at the work done by GiveDirectly and Watsi. One of the challenges with charity, though, is that you don't just want to spend the $10 optimally -- you also need to go back and tell your donors what you did with the $10, and convince them that they should give you $20 next year.