What is a mirror metric for % Rework in the context of Value Stream Mapping?

In Value Stream Mapping each quality-related metric has a “mirror” that expresses the same reality from the opposite angle. “% Rework” measures the proportion of work that must be redone; its mirror therefore measures work that flows through first time without needing rework. In the PeopleCert DevOps Leader courseware this mirror is called “% Complete & Accurate (C&A),” also known as First-Pass Yield. A high % C&A automatically means low % Rework and vice-versa, satisfying the definition of a mirror metric.

A. Lead Time – measures elapsed time, not quality; not the inverse of rework.
C. Cycle Time – process time per item; unrelated to defect rate.
D. Work In Progress (WIP) – inventory level, has no direct inverse relationship with rework.

1. PeopleCert. “DevOps Leader Official Training Material”, v1.0, Module 5: Value Stream Mapping, slide 14 “Mirror Metrics – % Rework ↔ % Complete & Accurate”.

2. Forsgren, Humble & Kim. “Accelerate: The Science of Lean Software and DevOps”, 2018, ch.3, Quality & Stability; discusses first-pass yield as complement to rework.

3. MIT OpenCourseWare, 15.760A “Lean/Six Sigma Systems”, Lecture 7, slide 18 “First Pass Yield vs Rework” – defines mirror relationship.