The final lesson states the boundary: this is deterministic quality-count arithmetic.
Deterministic counts
The calculations use deterministic counts.
deterministic quality-count arithmetic \text{deterministic quality-count arithmetic} deterministic quality-count arithmetic Improvement and scope The chart compares first-pass yield and final yield after rework. improvement and scope started 100; first-pass good 80; final good 95 started started 100 first pass first-pass good 80 after rework final good 95 measure count/rate meaning first-pass yield 4/5 good before rework rework rate 3/20 sent to rework scrap rate 1/20 scrapped final yield 19/20 good after rework improvement 3/20 final minus first-pass deterministic quality-count arithmetic only
Not capability
This does not model stochastic defects, process capability, or inspection error.
outside scope: defects, capability, inspection error \text{outside scope: defects, capability, inspection error} outside scope: defects, capability, inspection error Improvement and scope The chart compares first-pass yield and final yield after rework. improvement and scope started 100; first-pass good 80; final good 95 started started 100 first pass first-pass good 80 after rework final good 95 measure count/rate meaning first-pass yield 4/5 good before rework rework rate 3/20 sent to rework scrap rate 1/20 scrapped final yield 19/20 good after rework improvement 3/20 final minus first-pass deterministic quality-count arithmetic only
Not a cost proof
This does not model cost of quality or prove improvement.
outside scope: cost of quality and proof of improvement \text{outside scope: cost of quality and proof of improvement} outside scope: cost of quality and proof of improvement Improvement and scope The chart compares first-pass yield and final yield after rework. improvement and scope started 100; first-pass good 80; final good 95 started started 100 first pass first-pass good 80 after rework final good 95 measure count/rate meaning first-pass yield 4/5 good before rework rework rate 3/20 sent to rework scrap rate 1/20 scrapped final yield 19/20 good after rework improvement 3/20 final minus first-pass deterministic quality-count arithmetic only
Honesty note
This is deterministic quality-count arithmetic only. It does not model stochastic defects, process capability, inspection error, cost of quality, or proof of improvement.
deterministic quality-count arithmetic only \text{deterministic quality-count arithmetic only} deterministic quality-count arithmetic only Improvement and scope The chart compares first-pass yield and final yield after rework. improvement and scope started 100; first-pass good 80; final good 95 started started 100 first pass first-pass good 80 after rework final good 95 measure count/rate meaning first-pass yield 4/5 good before rework rework rate 3/20 sent to rework scrap rate 1/20 scrapped final yield 19/20 good after rework improvement 3/20 final minus first-pass deterministic quality-count arithmetic only