Quality Systems
Final yield says 93%. Only 79% went through right first time. The difference is a factory nobody built.
— %
Share passing every stage without being touched twice
Stage yields are treated as independent, which overstates the rolled figure when a single root cause degrades several stages at once - a bad fibre lot shows up in spinning, weaving and dyeing together, and the true joint yield is then better than the product of the marginals. Rework recovery is applied as one rate to every stage; in practice it varies widely by stage and by fault type, and a stage with unrecoverable faults should be entered with a lower recovery. The model counts units, so it assumes a unit is the same thing at every stage - for a route that changes unit of measure between kilograms of yarn, metres of fabric and finished garments, run it per segment rather than end to end. Rework cost is direct cost only and excludes the capacity opportunity cost, which is normally the larger figure.
Rolled Throughput Yield, First-Pass Yield & the Hidden Factory — free, with the formula and a worked example, at Textile School.