Makes sense to me, but I would like to have specific data that would help me understand: - How much money work needs to be invested for what incremental effect?

Makes sense to me, but I would like to have specific data that would help me understand: - How much money work needs to be invested for what incremental effect? - What kinds of investments are most effective? - How much does effectiveness depend on specific cultural factors, vs. being culture independent? And many more similar questions.