What technique helps to prevent defects in a process by designing devices?

Poka-Yoke is a technique specifically designed to prevent defects in processes by incorporating devices or mechanisms that make it impossible to make an error or that alert the user when a potential mistake is about to occur. This concept is rooted in the principles of error-proofing, aiming to enhance quality and reliability by minimizing the chance of human errors. For example, Poka-Yoke devices might include color-coded components that ensure parts can only be assembled in the correct order or sensors that indicate when a part is missing.

Other techniques mentioned, such as Root Cause Analysis, are focused on identifying the fundamental causes of defects after they occur rather than preventing them upfront. Value Stream Mapping is a tool used to visualize and analyze processes to identify areas for improvement but does not specifically design devices to prevent defects. Statistical Process Control utilizes statistical methods to monitor and control processes in real-time but does not inherently create mechanisms to prevent errors like Poka-Yoke does. Thus, Poka-Yoke stands out as the most direct method for preventing defects through careful design.