Quality Transmission Model and Quality Signal Theory

Quality Transmission Model (QTM) and Quality Signal Theory presents a systems-based framework for understanding how quality is transmitted, accumulated, and transformed across interconnected process stages. Rather than evaluating individual processes only in isolation, the approach considers how stage-level quality performance contributes to overall system-level quality. The framework extends conventional measures of defects, defectives, yield, and process capability by examining the transmission of quality through sequential and interconnected processes. It provides a basis for identifying where quality losses occur, how those losses accumulate, and how upstream performance influences downstream outcomes. Quality Signal Theory complements the transmission model by treating observed quality measures as signals of the underlying condition of the process or system. Together, these concepts provide a foundation for system-level quality measurement, defect prediction, process improvement, operational excellence, Lean Six Sigma, and Quality 4.0 applications. Author: Dr John M. HigginsAffiliation: Six Sigma Training & Consulting (Pty) Ltd, South Africa