Key takeaways
Short answer: First-Pass Yield (FPY) is the share of units that pass first time at a single step. Rolled Throughput Yield (RTY) is the share of units that pass first time at every step in sequence. RTY compounds — even a 95% FPY at every step in an 8-step process gives RTY ≈ 66%. Plants reporting only FPY at each step miss the end-to-end yield reality. See also Rolled Throughput Yield vs Overall Yield.
First-Pass Yield is the share of units that pass quality the first time, without rework, at a specific step.
FPY = Units passing first time / Total units entering
FPY is a step metric. It tells you how clean the work is at a specific station.
Rolled Throughput Yield is the share of units that pass first time at every step from input to final output.
RTY = FPY(step 1) x FPY(step 2) x ... x FPY(step n)
RTY is a chain metric. It tells you how clean the work is across the entire process.
FPY at each step can look high while RTY is low because the penalties compound. Examples:
The reverse: to achieve 95% RTY across 8 steps requires 99.4% FPY at every step. Most processes do not measure FPY tight enough to know whether they are at that level.
Three patterns:
Rework that does not show up as scrap shows up as Performance loss in OEE. A line with high RTY runs at design speed; a line with low RTY runs slow because rework is consuming capacity.
Plants tracking RTY alongside OEE often discover that Performance loss correlates with low RTY — the rework was hiding in cycle time.
Highly dependent on number of steps and process complexity. Rough rule of thumb:
The number is less important than the trend and the per-step FPY contribution.
1. Reporting only line yield. Aggregate hides step-level problems.
2. Confusing FPY with Quality. OEE Quality counts good parts including reworked; FPY counts only first-time-pass.
3. Setting FPY targets that produce RTY targets nobody can hit. If RTY must be 95% across 10 steps, every step must hit 99.5% FPY — usually unrealistic.
4. Ignoring the rework cost in OEE. Rework is Performance loss masquerading as Quality success.
A modern platform captures FPY per step from QC data and computes RTY automatically. It surfaces the per-step contribution to RTY so the dominant FPY problem is visible. It also reconciles RTY with OEE Performance to expose rework masquerading as Performance loss.
Fabrico's OEE module computes RTY from per-step FPY captured at QC, exposes per-step contribution, and correlates RTY trend with OEE Performance to surface rework loss.
See how Fabrico captures this automatically — explore OEE for manufacturing or book a demo.
Yes, in most usage. Both refer to the share of units that pass first time without rework.
Compounding. Each step's defects multiply through the chain.
OEE Quality at a single line is the FPY at that line. RTY across an end-to-end process is the product of FPYs.
Optimize RTY — but the way to do it is to attack the step with the worst FPY (highest contribution to RTY loss).
Theoretically yes if every step is 100% FPY. In practice, never exactly.
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