Rolled Throughput Yield is the probability of the entire process producing zero defects. This metric is increasingly relevant when a process has excessive rework.
Since this rework involves many of the 7-wastes and contains the hidden factory opportunity, it is relevant to guide the team in the right direction.
RTY is the product of each process’s throughput yield, TPY.
Using the same process as shown in the TPY example:
Calculation from above example:
RTY = Process 1 TPY * Process 2 TPY * Process 3 TPY
RTY = 0.800 * 0.739 * 0.804
RTY = 0.475 = 47.5%
There is a 47.5% of the entire process producing zero defects.
The baseline score provided in the MEASURE phase does not have to be a z-score and often the yield metrics are easier for team and other company employees to relate with and understand.
Another formula is shown below to estimate RTY if the defects per unit or defects and units are known:
Click here for a template that calculates RTY and other yield metrics. There are also a variety of other templates to a Six Sigma Project Manager.
Final Yield, FY.
Throughput Yield, TPY.
Normalized Yield, NY.
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