Survivorship bias: the damage you observe is conditional on survival. In 1943, the Statistical Research Group (SRG) at Columbia University was tasked by the United States military with determining where to add armor to combat aircraft. Armor plating adds significant weight, and every extra kilogram reduces speed, range, or payload. Because armor could only be applied selectively, where would it provide the greatest protective benefit? Ground crews surveyed returning bombers and mapped the distribution of bullet holes. Hits were visibly clustered on the fuselage, wings, and empennage. A naive reading of the returning-aircraft data would suggest reinforcing the most heavily damaged areas. Abraham Wald’s analysis showed why that inference could be backwards. Wald recognized that the observed damage pattern was conditional on survival. Returning aircraft showed relatively fewer hits in some areas—such as the engine compartments—but the damage distribution on aircraft that had be...
Human error is a symptom of trouble deeper inside the system. It is never the root cause. A third-shift operator crashes a $250,000 CNC milling machine during a tool change cycle, shattering the spindle and halting production for a week. When the morning shift engineering manager arrives, the immediate reaction is almost universally the same: "The operator wasn't paying attention. They were careless. They ignored the standard operating procedure." This is the default response in many organizations. When a failure occurs, the instinct is to find a human scapegoat. We write up the operator, mandate a "retraining" session, and close the incident report. This approach guarantees that the exact same machine will crash again. To fix the system, high-performing engineering organizations apply a philosophical principle known as Hanlon's Razor . Advertisement The Razor: Stupidity vs. Malice Hanlon’s Razor states: "N...