01 · Purpose
Why and when to use it
Use it to describe successful output while distinguishing process effectiveness from recovery through rework.
Who takes part?
The measurement owner works with people who understand the process and the recorded data. Statistical or measurement-system decisions should involve someone able to check the assumptions and study design.
02 · Application
How to apply it
Start with an agreed measurement purpose, explicit units and trustworthy observations. Identify missing cases and assumptions before calculating.
- Define acceptance and the unit entering the process.
- Record first-pass success separately from reworked success.
- Calculate first-pass and final yield with consistent denominators.
- For a multi-step process, define conditional step yields before multiplying them.
- Report scrap, rework and losses so the yield does not hide extra work.
03 · Example
A worked measurement example
Original fictional teaching example. Small datasets illustrate the method; they are not proposed as sufficient study sizes. Supplied parameters are assumptions, not estimates from a real process.
| 100 orders entering a process | Result |
|---|---|
| Pass first time | 90 orders: first-pass yield = 90% |
| Recovered through rework | 8 more orders |
| Final accepted | 98 orders: final yield = 98% |
| Two conditional step yields | 0.95 × 0.90 = 85.5% rolled throughput yield under the stated path |
04 · Interpretation
What the result tells you
Final yield can be high despite costly rework. Multiplying consistent conditional first-pass yields describes success through the sequence; unrelated marginal percentages need not give the actual joint yield.
Completion check: Clearly defined first-pass and final yield with rework made visible.
05 · Judgement
Mistakes and limitations
Do not count a reworked unit as a first-pass success. Branching paths, recirculation and inconsistent denominators require more careful treatment than a simple product.
07 · Reading
Sources and further reading
The tool list follows the accepted LeanTrainingLab overview and its reference to Six Sigma+Lean Toolset, second edition (Lunau, editor; Springer, 2013). The book chapters were not available for direct review during this build. Explanations, examples and worksheets are original teaching material. Further reading supplies professional background; local conventions are stated explicitly.