Positive Deviance is a somewhat unnecessarily complicated name for something deeply humane and useful:
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.
I’m collecting references to what Aid-Work 2.0 looks like, and this is part of it, I think.