⚠️ Disaster: Almost half of your team's effort is spent fixing what the other half broke.
This is the probability that a step is done perfectly the first time (no questions asked, no errors). Perfection (100%) is theoretically impossible in thermodynamics and software engineering.
Most teams believe if they have 90% quality at each step, their final quality is 90%. This is a mathematical lie.
The formula for Rolled Throughput Yield (RTY) is exponential:
Yield = (Quality) ^ Steps
If you have 5 steps (Dev -> Code Review -> QA -> UAT -> Deploy) and each is 90% accurate, your final yield is only 59%. The missing 41% is the "Hidden Factory"—effort spent fixing bugs, re-writing code, and re-testing.