For economic growth, don't focus on the total number. Ask about the distribution. Increasing world wealth by 20% would have minimal impact on making people's lives better if that increase is concentrated among the top 2%. It would have huge impact if it's concentrated in the bottom 50%.

So if you have a particular intervention in mind, ask yourself, "Is this just going to make the rich richer, or is it going to make the poor richer?" An intervention that eliminates malaria, or provides communication services in refugee camps, or otherwise assists the most disadvantaged, can be of great value without triggering your fears.