When creating a robust design, there is probably no more important consideration than identifying the correct parameters and associated values. A robust design is insensitive to anticipated variation and P-Diagram visually shows the relationship between what the system is designed to do, the anticipated noises the system will encounter and the correct parameters to achieve the desired outcome. P-Diagram can be an essential input to FMEA.
“Concern for man and his fate must always form the chief interest of all technical endeavors. Never forget this in the midst of your diagrams and equations.” Albert Einstein