Sigma is a measure of “goodness: the capability of a process to produce perfect work
• A “defect” is any mistake that results in customer dissatisfaction.
• Sigma indicates how often defects are likely to occur.
• The higher the sigma level, the lower the defect rate.
• The lower the defect rate, the higher the quality.
• Quality level at 99% is enough?
• Customer’s viewpoint: expect to get free of defect and do not accept any defect
• Customers compare quality of products or services with specification: If quality
is lower than spec, it is defect.