Statistical Process Control (SPC)

When to Activate This Skill

• "Set up SPC for [characteristic]"
• "Calculate Cpk for [process]"
• "What control chart should I use?"
• "Is this process in control?"
• "Interpret out-of-control pattern"
• "Conduct capability study"
• "What's the difference between Cp and Cpk?"

Purpose of SPC

SPC uses statistical methods to monitor, control, and improve processes by distinguishing between:

• Common cause variation - Normal, inherent process variation
• Special cause variation - Abnormal, assignable causes requiring action

Why SPC Matters