Statistical Process Control (SPC) is a statistical method used for separating special cause variation from natural variation in order to eradicate the special causes and to develop and sustain homogeneity in the process leading to process enhancement. The key element of SPS is continual improvement. It improves the predictability of the processes of the entire plant. Another benefit of SPC is that it assists in improving the quality of the product whilst minimizing the cost. This tool is embraced widely by the automakers for the reason that it only improves the quality of the product while reducing the costs but also enhances the image of the product for competing successfully in the global market. The key components of SPC include control charts that focus on continuous improvement and design of experiments. This tool is widely applied in the manufacturing lines.

It enables the workers to separate main causes of variations from the natural variations in the process. The process is declared as statistically controlled if all the special causes are identified and eliminated from the process and only natural variations are left. After the accomplishment of this state, the process is termed as stable and as per the 3-sigma process, 99.73% of the output can be viewed as within the statistical control limits.

The SPC differs from other quality and productivity methods in the way that it focuses on early detection and prevention of uncertainties instead of applying corrective measures after the problem has occurred. In any organization, TOC has broad applications; its implementation can result in decreased production lead times, enhanced quality of products and services, on-time delivery of the service and product, enhanced competitiveness and dramatic rise in the profitability. The theory is extremely beneficial for measuring and improving the productivity as it identifies the core constraints that can limit the performance of the system or the processes that act as a bottleneck and can be utilized to remove those constraints or bottlenecks; thereby, achieving higher productivity