I've meet the folks at GiveDirectly and think they are doing great work. That being said, effectiveness of dollars spent is just one measure of a non-profit. I

I've meet the folks at GiveDirectly and think they are doing great work. That being said, effectiveness of dollars spent is just one measure of a non-profit. It's similar to asking what's the best food. Each person has their own preference, much like each community/country has their own needs. There's no silver bullet to solving the world's problems. It's going to take a wide range of non-profits to address a wide range of problems. When determining your giving, a diversified approach will likely give you the biggest long term impact.