Lean, quality improvement & root cause · Working
Special-cause variation
Also called: assignable-cause variation
ELI5
Variation arising from an unusual identifiable factor.
Used in conversation
“Can we remove the ambiguity around special-cause variation before the process changes?”
Pitch context
You will see “Special-cause variation” in operating plans, procurement packs, supplier reviews and supply-chain reports when the discussion reaches lean, quality improvement & root cause.
Why it matters: In lean, quality improvement & root cause, the definition can change ownership, capacity, process, cost or safety decisions.
Sources & evidence · 3
Direct term-level sources and supporting source families.
- U.S. Bureau of Labor Statistics — Productivity programmeDirect source · primary · checked 2026-08-16
- U.S. Acquisition.gov — Federal Acquisition Regulation Part 15 — Contracting by NegotiationSupporting source family · primary · checked 2026-08-16
- UK Government — Groceries Supply Code of PracticeSupporting source family · primary · checked 2026-08-16