Yield Loss Cost Attribution Guide (Scrap/Rework/Downgrade)

Yield loss cost attribution addresses the challenge of moving beyond simple yield percentage calculations (e.g., First Pass Yield or Final Yield) to assign *monetary value* to quality failures. Scrap represents material discarded without recovery; rework involves corrective labor and resources to bring non-conforming units into specification; downgrade refers to dispositioning product at lower grade or price due to partial nonconformance. Accurate attribution requires tracing each loss event to its originating process step, identifying associated resource consumption (e.g., raw materials consumed but not sold, machine time spent on rework), and applying consistent costing methodologies—often activity-based costing (ABC) or standard cost modeling. The guide prescribes rules for distinguishing avoidable vs. unavoidable losses, handling shared overhead allocation (e.g., using driver-based apportionment like machine-hours or labor-minutes), and adjusting for recovery value (e.g., scrap salvage credits). Practically, it supports cross-functional decision-making: engineering uses it to prioritize process improvements, finance validates cost-of-quality (COQ) reporting, and operations benchmarks line efficiency against true economic impact—not just throughput. Integration with MES (Manufacturing Execution Systems) and ERP data streams ensures traceability from defect detection to cost posting, enabling real-time loss visibility and predictive analytics for yield risk mitigation.