IPC-9191 reflects the principals of statistical process control (SPC) represented by ISO/DIS 11462-1, "Guidelines for Implementation of Statistical Process Control (SPC) -- Part 1: Elements of SPC." This document outlines the SPC philosophy, implmentation strategies, tools and techniques and describes the provisions for implementing an SPC system in the electronics industry. The tools and techniques covered in this guideline are also used for relating process control and capability to final product requirements.