Here are two compelling reasons for using SPC:

• Quality is best at the target value.
  


• All processes vary.
  

Here are some more reasons:

• Better reputation. Your customer will notice the difference compared to your competitors who do not use SPC.
• Better quality. You will get early warning signals before you start producing defective parts.
• Lower reject costs. The frequency of rejects will almost invariably fall.
• Clearer objectives. Every member of your workforce will read the process the same way.
• Less stress. The work load will, as a rule, become lighter.
• Skill enhancement.  Production personnel will gain a whole new awareness of their work and their processes.
• Cost savings. High process capability reduces the need for final inspection.
• Fewer stoppages.  Incipient machine faults are detected early, which facilitates condition-based maintenance.