"You are looking only at the survivors," Arthur replied. "Just like Abraham Wald and the bullet holes in World War II."
"To test the hubs, the machine blasts them with a massive 12-volt electrical surge to see if they hold up. The weak hubs fail immediately and are thrown away. The strong hubs pass. But what about the hubs that are just okay ? The surge doesn't break them immediately, but it severely weakens their internal circuitry. They pass our test, we ship them, and they die a few days later in the customer's hands." The Power of Mathematical Thinking
For three months, Apex had been losing millions. Their flagship product—the Neural-Link micro-hub—was failing at an alarming rate once shipped to customers. Yet, every single hub passed the factory's final diagnostic tests with a perfect 100% score. "You are looking only at the survivors," Arthur replied
The lead engineer nodded in agreement. "We have run the numbers. Hubs with serial numbers ending in even digits fail at a 15% rate, while odd digits fail at 9%. We should focus our sensor upgrades on the even-digit assembly line." The strong hubs pass
"Wait," Arthur said quietly. "If you replace the sensors, you will waste millions of dollars and solve absolutely nothing."
Arthur recommended a simple, mathematically sound countermeasure: reduce the testing voltage by half and use a non-invasive thermal imaging sequence to detect internal stress instead of shocking the hardware.