In every village, there is at least one woman (usually a few) whose children are healthier than the rest. For whatever reason, that woman is better at navigating the complexities of village life and child nutrition. That woman has knowledge and skills which can be taught. You find her, you learn from her, you support her to teach her peers. That is positive deviance. Find the people who deviate from the norm by being more successful. Learn from them.
The original positive deviance programs were nutrition programs, with a specific structure and methodology. These are some nice examples. Positive Deviance remains one of the most powerful tools we have for improving nutrition in the developing world. You can also, however, use the ideas behind positive deviance for more than just nutrition.
Every systems has its positive deviants. People who are better at surviving within it. You don’t need a bunch of outsiders to or foreign experts to find ways to improve your system. Most of the knowledge you need is already there. It’s a profound and powerful idea. It means you improve education by learning from the teachers and principals of high-performing schools. It means you make childbirth safer by talking to maternity nurses and ob/gyns. It means you value the knowledge and experience of the people in the developing world.
When you want to make things better, look inside first. Learn from the people who know it best. After that, bring in your outside experts. See of they have anything add. But most of what you need to know is already there.